I personally want to have the ability to read any bill that has been introduced. THOMAS is a good system, but horribly outdated. It could be made so much better. But we make do with what we have.
Improvements to the system should be that the database is updated in real-time, or at least as close to real-time as possible. There is no reason why this shouldn't be possible.
My guess, however, is that reps want not to be able to be accountable for their votes. Not many representatives have easy access to their voting record on their official web site. I know my old rep did (Frank Wolf) but my current (Jim Moran) does not. While the information can be found on THOMAS, it adds an additional step.
I know a few months ago, DC Counsel put an unpopular bill available online for comment. It was passed and when it finally it the news, there was outcry. The counsel said, "But you had a chance to comment." The problem was that they hid the bill on their website in a rarely browsed section, obfuscated, and ultimately in a place where no one would think to look. Stepping aside the fact that the news should have picked this up before it was voted on, the fact is that the DC Counsel followed the letter of the law, but not the spirit.
Every politician must be not be trusted, even if they are from "your party" or even if you voted for the guy. The framers had this in mind when writing the Constitution.
The thing that saddens me is that the original intentions of the Founding Fathers has long since gone: a government of the People, by the People, and for the People. I don't see this changing anytime soon.