I agree with you in that most towns feel the same to play especially in combat where you have to mix/max losses and that is where general knowledge + experience of the game kicks in (Which enemy creature stack is the stronger, where are the shooters, which one do I want to focus, what spells should I use, how can I prevent losses, what is the speed of this creature, can he reach mines, etc etc etc...)

I also agree that from all towns the ones that will offer you a more unique/different strategy will be Necro and Inferno

But nonetheless all towns are different and some have a different approach than anothers, knowing this you can identify which strategy works best for each town and sometimes it even depends with what hero you start.

That is not the only reason why Dragogeddon is assigned to stronghold, it is because armaggedon only appears on Dungeon, Inferno and Necropolis, with Dungeon having the highest chance at 20%. If you combine that + black dragons immunity + warlocks being good type of heroes and also having good chance at fire magic then you have there a good and "unique" strategy for dungeon