Keep in mind, RPG parties are an archaic holdover from PnP days. In a PnP setting, playing with a group of friends, parties make natural sense, but for a single player game, they make no sense whatsoever. Yeah, they can add a little tactical depth, but generally don't, because most so called tactical RPGs (especially the more recent ones) don't use any kind of positioning. Mostly, they just add turn based overhead, long ass battle turns, annoying whiny companions with boring quests and romances, and other shit like that.
Solo character is clearly superior and more natural. If you want some bonds in a game, just create interesting relationships with NPCs, Witcher games gave a master class on those.