so i guess there's 2 threads about T4s now?
on the AI chat: planetary annihilation (an rts) had a neural network AI, what they did there was they had the AI play against itself to create sample data. the AI started out pretty bad, but since they could just have the AI play itself with the game sped up, and just leave that running overnight, and the AI would improve every game, it eventually became a pretty decent rts AI (that is, it was pretty bad at expansion but otherwise it had some really annoying tricks up its sleeves)
on t4 chat: it's really annoying that once you get to the point where you have access to and afford T4s in AoW3, you just spam the singular t4 you have.
personally, my favored solution would be to create a variety of t4s and increase t4 access, so that even if you're only using t4s, it's not monostacks and the game is still interesting
another solution is to design every t4 in a fashion similar to the shrine of smiting: while shrines are extremely powerful and access to them is very worthwhile, their strength depends on having a large number of non-shrine units (and therefore t3) on the battlefield, essentially forcing the player to create varied unit compositions.
an important note about T4s: while theoretically the "weakness" of T4s is high cost, they're actually much more cost efficient than weaker units, mostly in part due to the battle size limit.
consider the example:
you have 6 manticore riders. your opponent has the equivalent cost in t1 swordsmen (approx 1 stack per manticore, so 6 stacks, or 18 sowrdsmen)
7 stacks can enter the battle. you have 1, your opponent has 6, that's 7 stacks, they can bring all of their t1 swordsmen to bear against you. your manticores probably die, but not without inflicting some decent losses
now lets say you have 18 manticore riders (3 stacks). your opponent then has 18 stacks of t1 swordsmen (108 swordsmen).
7 stacks maximum can enter the battle. you ahve 3 stacks of amnticores, so your opponent can levy 4 stacks of t1 swordsmen against you. 3 stacks of T4 manticores vs 4 stacks of t1 swordsmen does not end well for the swordsmen. in fact, assuming the manticores have martial arts training, their defense against the human swordsmen is an effective 18, while the human swordsmen's melee attack strength is 11 (i'm not taking medals or strategic spells into consideration here because this just a simple example). so every time the manticore whallops the swordsman for 22 damage after the swordsman's defense is taken into account (20 damage if the swordsman is in defense mode), the swordsman is only hitting back for 3 damage. so, essentially, the swordsmen lose the battle without killing, or even inflicting substantial damage to, any of the manticores. so, the guy who spammed t1 here just lost 1200 gold and accomplished almost nothing. the manticores can definitely go on to gobble up all the rest of the 108 (now 90) swordsmen, and very possibly don't lose any manticores in return.
to put the principal shortly: because t4 units have higher stats, they will take less casualties in combat, and thus you will spend far less replacing them. while this is an extreme example, it definitely plays out similarly vs higher tier units as well (3 stacks of manticores will clobber 3 stacks of racial t3s. while anyone can obviously point out that the t4s will win, what might be less obvious is that maybe 3 or 4 manticores die in this fight, compared to 18 t3 units. the t3 guy lost way more resources than the t4 guy! devastatingly so!) going all in on t4s ultimately saves you a lot of money in the long run, just because you're turning losses into pyrrhic victories, and pyrrhic victories into total victories. throw in that all t4s are also incredibly mobile, and thus outmaneuvering a smaller number of them is actually fairly difficult, and the result is: there's really no reason not to go all in on t4s once you unlock them. you'll win more battles and end up with more money doing it.