He would as an addition, but not as replacement for Ross.
I'd like to think Ross will stay and challenge Gylfi and whoever else for a starting berth next season. It'd certainly breed some great competition.
The question is, whether Ross has that fight in him or not.
Sigurdsson is currently a better, more rounded and consistent player than Barkley, due to age and experience mostly.
But Ross is no spring chicken now in terms of how many games he has played, even though he is still young. He has improved his game a lot in the last six months, but yet many of the same inconsistencies that were present when he broke through have not been ironed out.