I too am a bit perturbed by the lack of a premium edition for the X-Box, but I can understand Midway's reasoning.
I don't think there's much Microsoft or any third-party publisher can do at this point about the rapid decline in game sales. With the way the market seems to be going this year, the X-Box's biggest competitor is neither the PS2 or the GC, it's the X-Box 360 itself. Price and game selection hardly seems to be the fore-most thing in the consumer's mind. This is also a damn shame, because I think 2005 was a fantastic year for the original X-Box.
The PS2 is long past its prime in my opinion (2003 or so,) but it still has the brand-name clout and the market penetration to drive sales. Sony has won two console wars in terms of sales and while the machine is not much more powerful than the Dreamcast, it's still maintained its hold on the average consumer. I hate to say this but I think the only people buying GC and X-Box titles anymore are hardcore fans or people who only own one system of the previous generation. Which again is a damn same because I currently buy a PS2 title about once a year. (My last purchases for the PS2 were Kingdom Hearts 2 -- 2006, God of War -- 2005, and Katamari Damacy -- 2004.)
Much like ebm, I prefer X-Box ports for multi-platform titles simply because of the support for higher resolutions (usually 480p,) and the X-Box Live infrastructure. And like ChiefThunder, the only thing I really care about on the premium disc is the video footage. UMK3 is a nice bonus, but I have little love for that title. Here's hoping to either Midway putting up the videos on the MK:A website or somebody releasing a copy on YouTube.
Now as for UMK3 being on X-Box Live Arcade... Yeah I suppose X-Box 360 owners do have that perk, but I want the videos dammit!
What most people don't realize is that there's also an X-Box Live Arcade for the original X-Box. (It requires a disc that you must mail order from Microsoft.) However, the support for the original X-Box Live Arcade was always rather poor and now near abysmal with the sales of the 360. The last Live Arcade titles released on the X-Box were thankfully a batch of Midway titles: Gauntlet, Joust, Robotron, and Smash TV. I'm sure the X-Box could handle a title such as UMK3, but I don't forsee Microsoft even bothering with the level of sales unfortunately.
So with that diatribe out of the way, anyone interested in selling their premium disc for the NTSC PS2 version for oh, say 20 - 25 US dollars plus shipping? :D