A great game that takes the Xcom combat style (shared initiative) and puts it into the world of a RPG is Wasteland 3. Highly recommend if you haven't played it (not for co-op though, apparently that is very buggy).
That game gives you an in-game HQ, and there you can basically manage an entire roster of characters. Although unlike X-com, everyone auto-levels up - I suspect the developer realized that if that wasn't in place, people will just use their core 6 party members all the time.
It's also got an interesting set-up in that it limits the number of story companions you can have, and gives you at least 1 extra slot to build another PC of your choice. I.e. you can have 4 story companions and 2 PCs, or 4 PCs or 2 story companions.
