Imho, doing the campaigns right in a game like this is the most difficult thing to do, because mainstream game reviews will always concentrate on the campaign(s) for a couple of understandable reasons (teach the game on the fly, expected to showcase what the game has on offer), going so far as to judge playing time purely of how long it takes to play the campaign(s). However, game development doesn't stop a year before release, but the more technically complex campaigns are, the earlier work on them has to begin.
To give an example, in AoW 3, let's assume cutscenes with voice acting, and imagine Rogue campaign featuring a cutscene with an evolving scoundrel - obviously to assassin, because that's how the game was at release. You have the cutscene, you have the voice acting, you have the story, they all cost money to produce - and shortly after release it's clear that this could have been better solved. So when you change the Scoundrel Evolve to Lesser Shadow Stalker your campaign is suddenly flawed - which means, you can't do it.
Then there is this "take them by the hand" feeling many campaigns nowadays have. It SHOULD feel as if you had to find out what to do, make decisions, be allowed to screw up ... Often it doesn't, though. You are just collecting objectives, toiling them off, being sent from a to b to c and back to a, following a script - which seems necessary if you want to tell a story in the correct order and catering for any alternative way players might find with the right messages and cutscenes would just be too expensive.
Which simply means, on one hand, telling a good story over the course of a few maps is cool, but in MY opinion a campaign MUST have replay value, otherwise you are just wasting assets for some flashy icing. With the story being told after a playthrough, the replay value has to come via variety of gameplay, and obviously Triumph is on the right track here.
I think, the best game of the genre when you consider campaigns only, is (still) Disciples 2 with unlimited replay value and an interesting story played from 5 different perspectives.