a few things: I know almost nothing so this will likely take a long time if at all. I didn't realize hex editing was necessary to fix bugs so that might be out.
And to be quite honest I don't even know where to begin.
There already are some decent patches designed by others here years ago to fix a lot of the graphical glitches.
As far as I know Revolution does use some form of tiles but they are quite small. I have said elsewhere however, that at least for designing a game I myself would prefer tiles/blocks over actual pixel physics.
First thing to fix which would be simple but very handy; remove the video files from the game. Reason: ccxeplore said somewhere that the only reason you need the CD to play the game is the movies/videos during game [these play after each level ends] which for some reason is the only asset that isn't saved on your harddrive during installation.
Of course one could somehow fix the issue of them not being saved to harddrive or whatever, idon't care as long as you don't need the CD for the game to run. Personally I find the videos (while cute at first) just get annoying after a while.
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as to designing an editor I guess I would create a stand-alone program that can create level files to simple put in place of the game files, at least temporarily.