I doubt it would burn developer hours as there seem to be a team in EA/BioWare porting games over both SW: Knights of the Old Republic games have made the move this last year. It also seem that the other major developer houses (ie NCsoft, Blizzard, Trion) are providing Mac client as part of the PC platform. It make sense as you are able to generate more revenue. I think that while there will still be a Windows Vs Mac debate the days of developers only supporting one or the other are starting to disappear.