Yeah defo, I've never been a big slater of him (I don't think), but certainly wouldn't have been too bothered if he had left in January, considering our other options.
As I said though, if he keeps missing a few games, then it takes a few more to get his form back, there's a judgement to make on whether you can keep someone who will only be available / match fit for potentially half your season. I think the same of Besic really, a good player, but no good having a good player for only 10 games a year.
Hope I'm wrong and he (JM) keeps fit, as would give Koeman a selection headache, and more importantly offer different options/combinations.