Couldn't you somehow add a different AI that would play like a seasoned player? Have the people making the HD mod and HotA thought about this?
Something real and relatively simple that could be done today is to enhance the AI through additional "AI cheats." As a reminder, the NWC AI cheats included increased income by a certain multiplier, Flight if Water Walking is available, a town portal even on cursed lands, the ability to escape from battle outside of its turn, etc.
Some additional cheats were introduced in the Master of Puppets mod. The mod itself is far from classic, but the specific additional cheats are actually quite in line with the original game.
It's not that difficult to adjust the cheats so that the AI players are competitive with humans. The community has been playing "poor Heroes" for the second decade now – the main opponent (besides the human player) is the stationary monsters on the map, resignedly awaiting their fate. The game's potential is, of course, much greater than that. After all, it's much more interesting to fight "monsters running around the map" (and even using magic).