I wonder if they'll have bothered fixing all the bugs still present in OS 2.43 and added in 2.53MP

Is this emulator available for the public yet?

From the screenshot, it may be a special version vaguely simulating the behaviour of the calculator, like TI-Nspire Computer Software is, rather than an emulator, like all community emulators are.

Is it me or does the interface seem a bit un-finished, it just looks like a bunch of text.

It's most likely 1 to keep it as compatible with the TI-82-84 series as much as possible and also probably to purposely not make it look as fancy as the TI-Nspire so that people might still consider the more expensive TI-Nspire CX instead of the cheaper TI-84 Plus C Silver Edition. This is probably also to make sure the fonts remain easy to read. Serif-based fonts such as Times New Roman, used on the Nspire, are not very easy to read on a screen.

I think that some talented ASM programmers *hint hint nudge nudge cough cough those on Omni* should make a shell to run 84/83+ progs on here!

Most programs should be compatible, but I doubt there is a way to have a shell that would allow ASM programs to run.

That would be simple for BASIC programs, but how would you implement that with an ASM program?

You'd have to change the programs themselves then it would no longer be a shell, but more of a patch to programs to make them work.