I would almost agree, apart from the dribbling part.
What you call as "gliding though" is indeed his best offensive weapon, but it is not dribbling...
It's an unexpected move by a relatively slow player, who is otherwise good and even more confident, but it has nothing to do with dribbling.
Dribbling is what Messi does, often Coutinho does, and even Busquests does with very quick ball control, where the opponent "thinks" he will end up in a position, but he actually turns to a different one.
Roberto cuts through (or between) two players, it is unexpected, zealous and brave, but it's not real dribbling as such...
Semedo however has better (not perfect or even outstanding) dribbling skills, which one could easily see during his first 2 or 3 Barca matches, when he had tried such a thing. After that, most probably he was told not to do it, so rather he makes those dull back-passes but the skill is in him, believe me.
Semedo, before all, lacks confidence and that is the reason why he tries less and less compared to what he would be capable of.
(If one carefully watched his moves without the ball recently, could certainly notice that he made very promising fast runs alone, but for some reason never actually got the ball. That also shows the level of confidence of the other players - in him). Semedo would be a much better player in a team that is faster, more straightforward, compared to the outdated and boring taka-tiki-chiki-wuki...