Yes, for almost all factions, you need to invest resources to acquire an ultimate ability, and that’s not always a good thing. Because you can develop a character better without it and still win. Let me give you an example. I had a Necromancer, well-developed, he could resurrect a huge number of units, Darkness was also well-developed, and so were the other skills. But I became curious to see how good it would be if I could get the "Scream of Terror" ability. I did, and the ability itself is, of course, great, no doubt about it, but the Necromancer lost quite a few useful properties because of this, and in the end, it turned out not as good as it was before. IMHO, you don't need to upgrade the ultimate ability for everyone.