Added 17 minutes ago
Necropolis could have an Altar (of sacrifices) for the living instead of the missing level 2 market, where a random artifact would be given as a gift each week. For the Barbarians, instead of a level 2 market, "Chambers" might be a better fit, where prisoners would be brought in each week to be sold as live goods. The prisoners could be any random troops, from Barbarians and other factions to neutral troops and even elementals and phoenixes. The Nagas could receive gold and artifacts from shipwrecks in a "Glimmering Abyss" location. And Inferno is fine as is. They can do without a level 2 market.
Added 11 minutes ago
That would be a disservice. All blinding-type spells would immediately become useless, or you would have to skip turns to avoid hitting the blinded unit. We've already been through this when we were shooting our own army with our own archers. Although, of course, it's worth thinking in this direction.
Added 45 minutes ago
It would probably be even better if, in a captured Castle, you could rebuild individual structures of your choice, or just the castle walls, instead of having to rebuild the entire Castle at once. This would be cheaper, and you could keep the unique features... For example, like the Nidus worms or the Orcs' chambers.
Added 21 minutes ago
Meaningful global changes in the 6th installment would make the wait for the sequel more bearable. And those who haven't purchased the game yet wouldn't mind shelling out for a license... Anyway, someone else will be making the 7th installment...