When I use gnomes, they're tinkers. They see the most use in Dragonlance and Spelljammer. I'm sorry to see them go in the 4th edition PHB I, but I suspect we'll see their return in the PHB II as part of the expanded core. It's just a way to condition the consumer into thinking that the core is continuous.
I don't see what the big deal is, the odds of gnomes being included in a future Races text is pretty much a given. If after upgrading your campaign to 4E you simply *must* play a gnome then just shoe-horn the version you want (from whatever previous iteration of D&D) and give 'er. Fact is, by virtue of adapting something to your needs you're more likely to create something that fits closer to what you want than merely relying on the outcome of a published work.