I don't think its unpolished as such its just they didn't expect the uptake it had and they haven't managed to scale the server platform as quickly as they'd have hoped. It takes time to add server hardware in and the relevant connections etc
As much as I'd like to think that, they really should have the experience from TDU1 and the problems that had at launch. OK so it wasn't over as many platforms at once (was only on 360 originally I think?), but still they should have realised there would be a significant server load.