While Jenkins was a failure as Wales coach, on the face of it he did a decent job with Llanelli/ Scarlets. However if you look at how that region are performing under Phil Davies, it's possible to say that Jenkins didn't get the most out of his old club.
Jenkins certainly wouldn't be a bad appointment but I think there are better candidates. Any one of Michael Bradley (bided his time with Connacht and Ireland A and has done well in both cases), Matt Williams (excellent with Leinster, less so with Scotland), Eric Elwood (outstanding job with the Irish U21's but probably a couple of years too early) or Alan Solomons (a success wherever he's been except for Northampton) would be a better appointment in my view. All know the Irish system and are already well versed in the talent pool available.