Skeletons
Anything other than Exhume. Exhume is what makes skeletons playable, turning a measely three into a glorius five. If you didn’t read the talent text carefully, note that they still deploy as 5 when dropped onto enemy towers.
Bloodmage Thalnos
At the moment, anything other than Bane. Drain Life was once extremely, extremely powerful but seems hard to notice at the moment. Dominance has the problem that there are 3 spells that cost more than 4 one of which is Deep Breath, only obtainable after defeating Onyxia. Living Bomb has niche uses, but is still not more efficient in terms of gold per level for Thalnos with the talent.
Cairne Bloodhoof
Aftershock is noticeably worse than Reincarnation or Plainsrunning. A daze effect on a melee mini just does not compare with coming back to life, or 50% increased movement speed.
Earth Elemental
Shrapnel Blast means giving up Obsidian Shard or Ready to Rumble, both of which significantly help the unbound tank do the job of tanking, rather than dealing damage in very specific scenarios. Shrapnel Blast is Shrapnel Last.
Gnoll Brute
Rabid reduces the cost of a Gnoll by 33%. Thick Hide reduces incoming physical damage by 50%. Pillage increases the damage to buildings, on a slow, cleave mini. Pass.
Goblin Sapper
Crude Gunpowder adds a small amount of damage on death. This would be okay but giving up 50% movement speed on fragile minis you want to send screaming to their death is not a fair trade. Extra BOOM is mediocre but defensible for adding 50% more damage to barracks or bosses.
Hogger
Fatal Frenzy is just far too niche compared to the scaling potential of Ham Hock or the poison synergy of Spoiled Meat.
Meat Wagon
Meat and Bones appears to be a rare talent that might actively make your mini worse. Giving up every second swing to spawn a single skeleton is a horrendous tradeoff, made worse by giving up the strength of Filet Trebuchet, which makes Meat Wagon the longest range mini in the game.
Quilboar
This is an odd one, because while Quilboar is an excellent mini, all the talents are rather low-impact. Nevertheless, Bramble Burst still seems to be Dunce of the Dumpster. The poison is a little faster now, but a single tick of poison is only useful in very, very specific scenarios.
Raptors
Strength In Numbers seems to be the reason to pick this mini in the first place, as the stacking damage bonus gives the raptor swarm an extremely high damage output. Other talents just aren’t good enough in comparison.
Rend Blackhand
Not only is Scale and Steel one of the most powerful talents in the game, Legionnaire has the problem of occasionally making Rend worse, as the Drake/Rend dismounted combo gets carved down by cleave or AoE damage. Flaming Soul is also excellent, adding an extra 6g spell onto the already stacked mini, which makes Legionnaire the clear worst.
S.A.F.E. Pilot
Gnomish Muttonizer is another case where the other talents are very good and this one might actually make the mini worse. As of pre-release, the polymorph hits a single target, making it a very slow way of disabling a single mini, as well as giving up the damage on that initial blast. The other two talents help our Gnomish Pilot do her job, so take those.
Sneed
Mine Is Money, Friend! seems much worse than a bunch of extra free gold from Lead with Greed or extra levels from Land Grab. Lead with Greed works without even playing him, and Land Grab make the 5g unit into a powerhouse. An extra miner is a tough sell, considering how slow and expensive Sneed is.
Whelp Eggs
Rookery and Flame Burst allow eggs to be deployed aggressively, taking towers and blowing up the ranged minis you deploy them on top of. Chromatic Plating could be egg-cellent but the taunt only pulses once, making it a very low-impact choice compared to the others.