Ernest stands supreme in risk/effort/rewards for clearing normal minion waves. It’s seriously not even a challenge for him and takes minimal effort.
For Thralls, I find ,even with the changes, Montana still stands supreme. It’s almost no effort and very low risk for him to walk right up to a Thrall point his mini gun into their tiny little head and just completely melt them away.
Galilea is one of my favorites to wave clear with. Jump into middle, desecrate, start swinging. It’s freaky how much fun that is. Tactically, after I desecrate, I always single out the Shepherd or lacking that, biggest minion first. After that scatters them I start cleanup. The only thing that prevents me from putting her at the top is the risk, at early levels without support, Galilea can take quite a beating from the waves.
Caldy is also good, that blind of his can be a lifesaver for pausing waves, but in my opinion it just takes him much longer than any of the above characters to clear a wave. Effort vs reward wise, he can do it, but I wouldn’t put him towards the top. For Thralls he is definitely better, but when he does get hit by their charge or spear it’s much more noticeable than on a Montana.