TB provides more tactictal depth than RTWP. Nothing beats the Jagged Alliance 2 and Silent Storm combat engines so far. When it comes to fantasy RPG, TB might prove boring because a player tends to always use the same feats, spells and capacities. Change should come from a variety of situations, the maps, the opponents, the weapons, the strong and weak points of the foes ... What XCOM 2 does very well.
RTWP provides more dynamic combat and faster resolution but sometimes turns out to a mess especially when high levels spell casters are involved. Against bosses or during hard fights a player may have to hit pause every second to guide his /her party.
Anyway both can prove pleasant to play if the development of the story, characters, lore, overall background are appealling. I do not doubt that RB will offer it!
As for party composition, I personnaly prefer full fleshed companions rather than bland followers. Others prefer to tailor their party. Ceres Game made a good call giving the two options.
In my NWN2 mods, companions are full fleshed and I give the choice to the player to select their classes/races among a range of choices.