As an exception to the rule, yes. But it would still be a daft decision.

Hardly, I find it hard to believe there are still that many people buying gaming class hardware and still using an OS that can't fully take advantage of it. Would you want things to be held back because they wouldn't run on windows 95, back when XP was modern? Because it's the same situation here.

Lots of people are still using XP right now, Bethesda is guaranteed to lose sales if their PC audience was limited to Vista/7 users.

http://store.steampowered.com/hwsurvey/ suggests that only around 56% of its users have both a DX10 compatible card and OS.

There's a difference here.

1.) Windows XP is far more stable and just in general a far better operating system than Windows 95 (or 98 or especially ME). Windows 7 is way better than Windows Vista, but XP (in my opinion) is actually a superior OS to Windows Vista. Windows 7 is good. Is it universally "better" than XP? I don't think so, other than the silly "no DX10+ for Windows XP" shenanigans.

2.) The Xbox 360 using DX9 shows it will have to be able to run on it, so making the PC version require Vista or 7 would make zero sense. Providing DX10 or DX11 options for PC users would be fine.

3.) On older hardware XP runs games far more smoothly than 7, since Vista and 7 are far more bloated than XP. 7 may not be as bloated as Vista, but it's still bloated. This means requiring Vista or 7 will lock out some potential customers that would be able to run the game under XP but not on Vista or 7 due to those operating systems hogging system resources.

I think the game should look as good as the console versions on older hardware. Modest system requirements will help it sell to far more people. There can be options to utilize modern features and more powerful hardware, but the game should look good on a machine that can easily run Oblivion in my opinion.

I think one of the major problems with computer gaming is the constantly rising system requirements with new releases. If anything I'm glad the consoles are holding things back. A 6-8 year console life cycle means developers need to make the most of technology rather than just constantly adding more bells and whistles without thought of taking advantage of one iteration of hardware to its fullest first. This 6-8 year cycle will allow the potential pool of customers to be much larger, since the customer pool won't be limited to people that upgrade their PC every year or two or get a new one every 4 years or less. A PC lasts many people 5+ years, so the game being able to run on a powerful computer of five years ago would be a good thing, at the very least on lower settings with the game still looking decent.

As is echoed in many of my posts though, I'm all for options. I think people with powerful hardware should be able to take advantage of advanced features. I just don't think those with more modest hardware should be locked out.

What the guys above me said. The Steam survey says it all. Beth will miss out on a large portion of the PC-market if they ditch DX9 support.

And surely it's not for Beth to help Microsoft push people to Win7, that's Microsoft's own task. Microsoft made the decision to not support DX10/11 on anything older then Vista, not Beth. Microsoft decided to jump into the console market and maintain a strictly DX9("+") console platform, effectively stopping the need for continuous upgrades on the PC as a side effect due to vastly increased cross-platform releases. It's due to Microsoft's policies that we're dealing with a large demographic who aren't willing (nor required) to keep up in updates, causing a schism in PC-gaming.

Bethesda on the other hand is here purely to develop and sell games. Since the game Beth is developing is already developed for a DX9-only platform, there is no reason at all why Bethesda shouldn't support DX9, neither technically nor economically.

I may be running a DX11 GPU with Win7, but all together that's just 5.6% of the total PC-market. I do not expect Bethesda to limit it's customer base just so I can have my cake.

I think you're mistaking "bloated" for "actually uses your hardware", but that's beside the point - anybody running on "older hardware" doesn't have gaming class hardware.
IMO, there is no reason other than "My computer is still from 2004" to still be running XP. I'm not saying the game should be DX>9 only, just that if it were I can't imagine it would affect a large amount of people who could play it anyway. Yes, there's a vocal minority who have the required hardware but are still running on XP, but it's time to move on. XP is 7 years old, now. When XP was launched, IE6 was the standard. When XP launched, the internet was new and shiny. XP doesn't support many new standards or technologies, it's insecure, it's slow, and it's inefficient on newer hardware.

I don't think "just because" is a good reason to start using an OS that (in my opinion) wastes system resources.

Let's be a bit more realistic too. "Gaming class" hardware changes every few months. There is no "gaming class" hardware universally. Until we know the system requirements, that term means nothing.

Thats why Im getting it for my PS3. Unless I get an HDTV for my x-box.

so are PC users going to, once again, get a dumbed down version because of consoles?

A lot of people are worrying about high system requirements when Bethesda is using a new engine they made for use on the current consoles.

...they are being silly.

The game will be released for Xbox 360 and Playstation 3 so anyone who can run Oblivion on PC with max settings should be able to run Skyrim as well (albeit not on maximum settings).