Reasonable on 13 December 2010
I'm actually hopefull it won't.
Vegas was another developer and they clearly struggled to add their code to the existing codebase - a common problem trying to build on someone else's code - and the developer's previous title was buggy too, so I think Vegas is a red herring that has to be judged alone
They now have ID Tech5 available plus Caramack, surely they'll leverage that for Oblivion 5? If so, I wouldn't expect too many bugs.
Try to be reasonable... its easier than you think...
