First of all its the best game turn based that i know and iam a big fan of all of them, but i can say that this one is the best of them all. So here is my suggestion for a long life of the game it will be nice to have some unique world boss in each game session that can be the last ambition of the compagny killing the random unique boss (one per game session) like the kraken, we need more monsters like these ( dragon, giant, golem, lich ) something really hard.
also battle sister (rare recruiting encouter) but it cant be charm by the hexe cuz shes a women kinda like immune against the singing mermaid.
mage( i noticed that some missions u can see that the guy wearing a mage robe ) i know its a low fantasy game but a rare encouter mage or cleric that cost alot to get into your party can be really cool. ( something like he can use already existed drop items to craft spell ) but just a suggestion on that i dont know how it can make the game weird at some point.
more DLC monsters and craftable items of course this make the world more alive to get more than just orc goblin undead skeleton and brigands … so more more more :P