Dunno about world class. Depends how you would define world class though. He has a long way to go that's for sure. So raw at the moment to the point he is handing the initiative to the opposing batsmen and putting more pressure on our pace attack.
I prefer Williamson bowling at this stage.
How is he going to get there without bowling?... of course Williamson is used a little more - and if you're referring to the last test you also need to consider who he was bowling to.
Preference to Williamson (and bowlers like him) is a direct result of exposure of/to white ball cricket. Test matches are very different - and IF we can develop Sodhi (or any of the other high potential young spinners we have) then the benefits are obvious, to most.
All spinners - and especially leggies will get carted from time to time... especially earlier in their career. Given the chance some learn and grow from that - others don't and fall by the way side.
But yeah, let's flag that - bowl Williamson more and perhaps even bring McCullum into the test team.
That'll keep the runs down for sure. Job done.