Bring out 3 gnome subraces simultaneously:
1. Gnome, +2 con, -2 str, F2P
2. Tinker Gnome, +2 int, -2 wis, P2P, free to VIPs
3. Deep Gnome, +2 dex, +2 wis, -2 str, -4 cha, tough favour unlock (or buy from store)
Gnomes have plenty of other traits that can be found here.
I wrote a thread suggesting gnomes here which developed quite a few different ideas.
One in particular that I liked is that rather than introducing the gnome hooked hammer (as we don't need more weapon types) to let gnomes treat heavy picks as 2 handed weapons with +1 damage die when their offhand is empty (so a heavy pick becomes a 2d6, x4 weapon in the hands of a gnome). This would give gnomes a nice melee niche.
New illusion spells are important too. There's a great thread floating around with practical illusion spells that could be introduced without too much harm while still being different enough that they would be good additions to the game.