We rely on his defensive capabilities far too much for him to be used effectively going forward. Ben Arfa roams around and makes things happen so we tend to accept him not tracking back, as it seems like he's not expected to defend all the time. With Jonas his tracking back to help out the defence is a big asset, so we can't afford to lose out on it by allowing him to steam forward.
I wouldn't be at all surprised if we looked at a new left sided player in the future and tried to fully transition Jonas into a centre midfielder.