If we're looking for someone to replace what Ramsey brings to the team, in terms of driving the ball forward by making deep runs from midfield, then Praet should be one of the first names on our list. I've seen some comments about him from people who probably haven't watched him lately, but the guy really is good.
He doesn't score or assist much, but people shouldn't get caught up too much on the numbers. He needs to improve on them in England, but few midfielders in Italy rack up the end product. It's a much more tactical game there, and the fact that Praet manages to control (and often raise) the tempo so much despite not being a deep playmaker is to his credit. Looking at Arsenal over the last two years one of our biggest weaknesses is that we become immobile far too often without Ramsey, and Praet will help a lot in that respect. Guy's a good dribbler but above all he's got a bit of fire in him.
The biggest issue is that I think he has looked better without Torreira, and an article I read the other week made the same point. Sampdoria have Albin Ekdal this season who's quite underrated; very capable defensive midfielder who dominates the short passing game, and he opens up space for Praet. Then again I have no idea how we're going to line up next season or what longterm role (if any) that we have in mind for Torreira.