Pjanic is more mobile on the ball and a better passing range. Not to mention he’s very precise with his passing and doesn’t ‘force’ the pass to the extent Jorginho does. Something I witnessed Jorginho do a lot this season, and in most cases it led to an opposition counter. City’s 1st goal against us when we were in control springs to mind.
In fact, I would say he more resembles Gilmour than Jorginho.
No idea who’s better defensively, but at this point it can’t be any worse than what we have currently. In my opinion it would be easier for Gilmour to transition in the squad with Pjanic than Jorginho.