One of the things that irritated me about 2.1 was that precipitation was completely broken and absent in OpenGL mode (on all OS's). I've compiled and played the most up-to-date "next" branch and that hasn't changed, at least for the Linux version. I know that OpenGL isn't the "official" mode, but it would be nice to have that regression fixed, especially considering that another branch has almost completely implemented working and visible slopes in that mode (all except for shadows on slopes). And it's not like it's never been in the game, cause it worked in 2.0.
Being a software developer myself, I know that fixing broken old features is often HARDER than making new ones, especially if it's multiple versions old. Still, it's one of the more visible issues that are most certainly bugs, as opposed to others (pixmaps) than can possibly be viewed as "stylistic" differences.
Keep up the good work ya'll. =)