This all makes perfect sense, especially considering the fact that a Guardians sequel without one of its most important characters wouldn't feel right. And Peter Quill needs to be an idiot in more ways than one, and what better way to do that than to bring back his smarter, more competent love interest? (Assuming alternate timeline Gamora is even his love interest.) Sorry, Peter. You done goofed when you punched Thanos in the head repeatedly and basically killed everybody.