Ya know, I've been an avid Windows only no matter what kind of guy since the dawn of it and still love Windows... but have recently picked up a MacBook Pro 17" 2011 Model with 8GB of Ram, the upgraded CPU, etc... and have to say... it runs Windows 7 better than any 'Windows' laptops with the same / near the same specs / price.
This has been my best Windows computer yet, lol. Anyway, back on topic... I'm really starting to enjoy the whole OS X experience, and although I can and do Bootcamp Win7, I'm in favor of OS X native clients... prevents the whole hassle of Bootcamping to Windows.
Blizzard (I know, I know, not the same... I get it...) has 18.9% of it's userbase coming from Mac... so the momentum and possibilities are there I would think, but I'm not one with any real experience in any of the departments of producing games, so I really can't say much other than I would support an OS X native client and although I have Win7 Bootcamped, have lately just gone after what runs natively, since none of the games out / coming out have really been that good enough to be worth the reboot.
Get a gaming company to make a game similar to DAoC with updated artwork / interface and that's something I would bootcamp all over until splooge came out. lol