The idea is not bad, but then the Elementals will lose their old, good Urgash's Call. In principle, it is possible to make it so that both skills can be upgraded, but one skill excludes the possibility of upgrading the other.
level four - still under consideration, most likely it will be a ballista with 0 speed, low initiative, and growth, but with decent health and damage (+ the fact that the faction will have 3 large creatures)
level five the Heavy Nomad will be replaced by a Black Samurai with a Hashima
the rest of the levels remain unchanged
(there were also ideas about level four - to put a mage there and add Landsknechts, but Landsknechts don't look good on anyone except the Warlord, and the Warlord is twice as strong as the Armored Spearman, it's no longer a Landsknecht, but a Dwarf Tank)
there is also a problem with dragons - the new canon says that a dragon has only one path of development
in general, there is a vampire model - you can make a Landsknecht on a vampire - a vampire is essentially a human, and the Armored Spearman are too short and stocky compared to the others - in my opinion, if you want to perfect everything, it is better not to make humans smaller, but rather larger - but this is not certain - you still need to compare. Based on the Warlord, you can make Einherjar. Based on vampires, if not Landsknechts, then Justiciars (elite melee units for humans - in other parts of Heroes, the analogues were Crusaders).
The ballista is an interesting idea - put a dwarf next to it and you have a full-fledged artillery unit (I sometimes play Total War: Warhammer - artillery looks very impressive there)
