>1) Option to play whatever portion of file you were able to
> download ( don't leave it as a .xlx file)
>2) Option to launch file while you download it.

Yes, should be there for mp3's and other file data types which programs can easily play when downloded partially. But if you give a random fragment of a MPEG4 file (divx) for MS player or Playa, it will have difficulties playing it. I have seen, that Playa can play the segment from the xlx-file, if it is the first one of the file.

A more detailed survey would be interesting: which byte ranges from a file are necessarily needed to be able to start playing it?

How much of this is inherent limitation of the compression algorithm (mathematically non-streamable)?

Limitation of a stupid file format (which packs essential algorithm parameter data at the end)?

Limitation of the player programs?

>3) In Transfers window, be able to select multiple files ( to
> cancel them, etc ).

"Nice-to-have". But only after stability is better. Don't add a single feature before stability is better!

When I have had any influence on software publishing schedules, I have always suggested: In January bring out a more reliable bug fix version, with no new features, no new bugs, no new optimizations. In June, when things are quiet in the workplace, bring out the version with new features, new optimizations and new bugs.

For beta software, make it a bi-monthly schedule instead of a yearly one.