As far as I know the only patch that was made for this game was made by Heuristic Park. You can find a link to the patch on the Ironwork's W&W front page (not the forums).
There is also a handy list in the BEST TIPS thread of what it does and what it doesn't do.
As for the frequent only one hit point increase when leveling, I never found that to be much of a problem. It generally was limited to when you had changed classes and as soon as your new class reached the level of your previous class everything worked out fine. My characters were never lacked hit points.
I play the unpatched version.
Wyv