I'm in middle of watching this video D8: Steve Jobs Onstage, and at (40-48 min into) the point where he talks about personal computers being like trucks and stuff and why they did not use stylus for their tablet.
So of course what I as a consumer want is the best of both worlds and not only the stuff that a finger UI is suitable for, but for increased usability and battery I could certainly sacrifice some of the traditional PC features (***).
My vision of a PC based tablet:
Make it similar as the ipad in terms of touch+mobile UI, then have in the bottom a physical stand than can be extended out of the bottom to make the tablet stand on the table in suitable angle. Then when external power, mouse and keyboard is attached, it will turn on a full powered PC. There should also be an extension bus, possibly a whole new bus that allows to bypass the internal circuitry of the tablet, essentially turning the tablet into just a display panel with a HDD that would still be in use so you get to keep your data available. Through the bus you could attach a small box that could contain in small space more HDD's, ports, another faster CPU+GPU for gaming and a beefier power supply. Essentially you'd have 2 PC's one inside the tablet and another a mini-pc for extensibility and longer lifetime like desktop PC's have with just one display. The display should be superb, so there's no need to buy another display. Cost cut on anything but the display and touch mechanism and sturdiness of the stand/robustness of case material, the desktop extension unit can contain the gaming-level GPU/CPU which tend to make 2/3 of a desktop PC cost.
It was also noted, that it's essential that everything is in one place, so you don't feel like you have 2 PC's. Thats why the HDD internal to the tablet unit is always the system HDD and the possible additional HDDs in the desktop extension unit are always some archive HDD's. The whole selling point here is that you don't need 2 PCs but you can buy a tablet with great display and then it will have extensibility to make it also last more than 5 years through the desktop extension unit that allows easy replacement hardware so it will serve both mobile and 3D gaming markets.
The touch+mobile UI there would be restrictions placed in app design and OS that would be enforced. This would mean enforcing only certain finger-touch APIs for control and restrict stuff that eats battery by removing availability of all APIs that cause polling style behaviour in the mobile mode. Then MS should also take a look at the most popular apps on the desktop that can be converted into usable in this mobile form and try to make those available at the announcement of the rest of this.
(***) but only if there were some guarantees (I'll explain) in place that make sure there would be no possiblity to do straight port of traditional PC app into the mobile touch mode (necessitating investment into the mobile mode app experience) which would make the product just look like a dinosaur with no innovation in comparison to the ipad. The focus needs to be on the mobile touch (w/o stylus) usability and the fact it can turn into a full power PC should just be "one last thing" as Jobs likes to say.