Those of us with slow Internet connections can relate - for me the recent versions take 15-30 minutes to download, plus time for Minecraft to load it on startup. It's rather hard to join a round of Safari Games on half an hour's notice when it takes that long to get the necessary version.
Thus, I suggest that the efficiency and size of the mod be improved next. Lag is a problem for all of us, and one that's been very apparent in the 4.x versions. It annoys us, it discourages us, and worst of all, it makes the game unplayable. And file size, on an old or 'light' computer, is sometimes critical.
As I don't have experience or direct suggestions for this, please speak your mind on the subject in the near-infinite space of this thread. Thank you for your time! =)
~Storm