So, keep the gnome abilities.
...
+Str - Half-Orc
+Dex - Elf and Halfling
+Con - Dwarf and Gnome
+Int - Halfling
+Wis - Dwarf and Half-Orc
+Cha - Elf and Gnome
While I do second the idea of moving elves towards sorcerer, being magical themselves and all, the idea of intelligent halflings seems to be off to me. When you think of the Halflings in LotR or Dragonlance, Halflings are anything _but_ intelligent. Add to that, that gnomes "tend toward invention, alchemy, or other technical pursuits". Invention and alchemy correlate with intelligence, so this should be one stat of the gnomes. Now somehow there seems to be a rule "1 mental stat and 1 physical" which makes it a bit hard to shift.
Looking at mechnical inventions, dex would seem a logical choice, but then elf halfling and gnome would have dex as a bonus stat - this seems kind of bland.Con seems to put many people off and str seems just wrong - so in the case of gnomes I really would vote to break that rule and give them +2 to int and wis and a -2 to str. Now they can be the studious Illusionist or the fey-and-land-attuned druid.
Apart from that: I really can't imagine a halfling wizard...could a halfling keep still long enough for reading just a single page of a spellbook? Also Halflings are uncharismatic to me, the are a nuissance, constantly chattering and whining for food...ok, yes, I do not like halflings.
My proposal:
Dwarf: +2 Con, +2 Wis, -2 Cha (stout and hard but grumpy)
Elf: +2 Dex, +2 Cha, -2 Con (agile and fascinating but frail)
Gnome: +2 Int, +2 Wis, -2 Str (physically weak but smard and dedicated)
Half-Orc: +2 Str, +2 Dex, -2 Int (Strong, fast, but dumb)
Halfling: +2 Dex, +2 Con, -2 Wis (Foolhardy, but fast and hard to squish)
Favourite classes:
Dwarf: Cleric or Fighter
Elf: Bard or Sorcerer
Gnome: Druid or Wizard
Half-Orc: Barbarian or Fighter
Halfling: Ranger or Rogue