Don't know how psyched I am for this signing. The problem with this type of player, the dribbling and gliding CM, is that you have to be so fucking extremely skillfull for it to matter at top level. Players in well organized teams aren't going to rush at you with no second thought making it easy for you to feint and glide past. Even if you're a one out of a thousand technical talent like Isco who can actually do it, that doesn't mean your contribution is automatically a blessing for the team.
For a CM at top level in modern football, let alone at Barca, passing and distribution should be the first, second and third priority. Thereafter, dribbling, defensive ability and shooting can be considered.