If you scan the various tier lists that people have made throughout the Rumble community, recommended builds, or even the PvP leaderboards, a few minis show up again, and again, and again. Whelp Eggs, SAFE Pilot, and Quilboar stand apart from other minis, if not in pure power than surely in presence.
Sometimes they get categorised as just 'unbounds', but while Skeletons and Earth Elementals are useful minis, they don't appear to have the same ubiquity as our troublesome trio. What makes them so good?
First of all, what's something they all have in common: They're unbound, and they're cheap. Both massively increase the versatility of the minis. Being unbound means they're unconstrained by any particular map geometry and can be played reactively. Being cheap means they don't clog up your hand. But the same is true for a Worgen, so there's more to the story.
Today we'll do a deeper dive on the three and their position relative to other available minis, starting off with Whelp Eggs and SAFE Pilot, before looking at the Quilboar.
The mascot of the Rumble series, this pink-haired gnome introduces you to the game and is one of the first minis you acquire. In many ways, it is fortunate that such a powerful option is given to you at the start.
At level 1, she has 210 health, which is fragile but not insignificant (enough to survive a Chain Lightning, even boosted by Jaina. She is slow to move (mitigated by her unbound trait), and her attack speed is one of the lowest in the game, at 2.4.
As a ranged damage dealer, she hits as hard as an (untalented) Pyromancer (170), albeit a fair bit slower, but the splash on her attack seems to be slightly larger, and her range a tiny bit longer. As a regular mini she would be okay, but clearly overshadowed by other options.
But she's not a regular mini, and this is where things get interesting. Her crash damage is 250, which is enough to kill her, and Pyromancer, and in fact, (almost) every single ranged or flying mini under 4g (the exception being Meat Wagon. This alone gives her a rather impressive niche, as Chain Lightning does too little, and Blizzard requires 4g, and there's no other spell to fit in this gap of backline killer. Holy Nova spends a portion of its damage budget on healing, and Execute or Polymorph require other sources of damage. Arcane Blast deals slightly more at 3g (300), but you need to have spent a previous 3g on 225 damage (less than her crash), or have the appropriate talent.
Even if she died immediately, you could consider her just for dealing lethal damage to a large variety of minis for 3g, instead of the 4g that Blizzard asks. This is pretty remarkable and makes it almost impossible for her to not get at least even value (unless, of course, you miss).
But what about her talents? She adds either Burn or gains Stealth + Ambush. Burn deals 240 damage over 8 seconds, bringing her total to 490. That's now enough to kill 4g minis like Necromancer, Flamewaker, or Firehammer. It's enough to kill the Dwarf from Mountaineer, or even the 6g leader, Sylvanas Windrunner. Likewise, with Ambush, she deals 2x on her first attack, coming to a total of 590. This is now more than Blizzard, and almost enough to clear the bulky 5g Ogre Mage! Admittedly, Blizzard is guaranteed damage and has added utility whereas the Pilot can be knocked out of stealth, but even the Burn talent comes remarkably close in damage output.
Safe Pilot would probably see some play just for filling the gap in damage 'spells' with no talents at all. For clearing backlines, she's already a really good option. With talents, she becomes one of the most efficient sources of damage in the game.
Leeroy Jenkins' bane, Whelp Eggs shares some similarities with Safe Pilot, in particular, once they have the Flame Burst Talent. Whelp Eggs are particularly potent against melee minis - first distracting them with the eggs and then, once hatched, soaring above, burning them down below.
They are more fragile than Safe Pilot in a few ways, having little enough health to die to a Chain Lightning and rather a short range, at 3.5 - just slightly above melee. This means that if something can hit them, they kill them rather quickly.
What they lack in defence they make up for in offence. Each Whelpling swings for 110, so after one wave of attacks they've done 330 - which as we noted before, was enough to kill all the ranged or flying minis less than 3g. Since the other mini has to pop the eggs, the windup on the next attack gives the Whelplings time to kill them first. So we have the odd situation that not only do they hard counter melee by mere virtue of being flying, they also can defeat any ranged mini at the same cost or less. This makes them very difficult to counter. Chain Lightning works well, and they can have the eggs popped by a melee mini followed by a supporting AoE clear them up before they can swing.
Flame Burst mocks such attempts. Each explosion does as much as a Whelpling attack, so a Pyromancer instantly dies to the 330 damage explosion from the three eggs dropped in her face. Even the Ogre Magi now falls, as 330 damage from the explosion combined with the 330g damage from the Whelplings themselves combine to just barely knock out the Ogre's 650 hp. Just as with Safe Pilot, Whelp Eggs are not just good unbound minis, they're very efficient sources of direct aoe damage that occupy a useful position in the gold curve.
Quilboar are a little different. As a body, they are fairly unremarkable. Low damage, acceptable amounts of health (even considering the Resistant trait), it is not clear from the numbers why they should be so powerful. But unbound tanks are disproportionately powerful.
The reasons are twofold: First, they can be deployed at will to preserve unprotected minis. Second, in many maps, positioning, not health, is the most important thing for a tank to establish.
For the first, imagine a clash between two armies. The lone survivors - a trio of Harpies. Assuming both armies were equally matched in gold value, are you now up three gold? Often, no, as many towers can immediately take down the Harpies at little cost to themselves. In many cases, minis outside of formation are dispatched so cheaply, so freely, that they barely represent any value on the map at all. But add an unbound tank to the mix, and suddenly those Harpies are back in formation and ready to shred. The rapid deployment ensures that no minis are 'wasted' by misfortune or misplacement on the map.
For the second, it should be noted that tanks in Rumble are terrible. Not because of a lack of fortitude or constitution - many of them can weather enormous amounts of punishment. Rather, because they fail to position the boss correctly. It is one of the most basic tanking skills that any player in an MMO learns, to turn the dragon's breath away from their allies.
But in Rumble, this is only available for most tanks by careful timing of the deployment of their support (or control of alternative lanes of approach), or the good fortune that this is one of the bosses that has no cleave attacks, nor long range conal AoE. This means so long as Quilboar (or Earth Elemental) had enough health and durability to act as a tank at all, it would have an enormous advantage over other tanks by mere fact of being able to position the boss correctly.
This poses a particular difficulty to balancing an unbound tank. If the unbound tank mini is playable, it probably ends up seeing a disproportionate amount of play because the primary role of a tank is to act as a multiplier for the rest of your army, rather than what they directly contribute in stats. Even though Core Hounds and Abominations are good minis, they'll always be limited to 'deathball' strategies that aim to assemble an overwhelming mass of force, rather than act as tanks for generic armies or situations.
What to do?
I don't want to end this piece with a call for nerfs. It is possible, probable, that Safe Pilot and Whelp Eggs need toning down. But both represent a real need for players in their armies - to take down ranged backlines at medium cost. A game where you can't do anything powerful is not a fun game. Likewise, the strategic potential of boss positioning that unbound tanks like the Quilboar or Earth Elemental adds genuine depth to the game.
For Pilot and Whelps, the fact that they are unbound minis I think is secondary to their up-front damage potential. What makes them so strong is their ability to act in the aoe damage role. For Quilboar, I think we do have that unbound minis are genuinely more powerful in a way that is limiting to the functionality of other tanks. Whether or not they can be toned down while remaining playable is hard to say, but another possibility is that other tanks need a better capability of protecting surrounding minis. We already see some functionality in that vein in General Drakkisath's resistance aura. Perhaps we can see more.