Now that's what I call lateral thinking. And a fine example too!
Having a gnome in spiked armour would be likely to increase the damage die by one increment, in addition to providing piercing damage instead of bludgeoning damage you'd receive from a kobold in leather armour only. So, you can effectively get more bang for your buck purely through a careful selection of which enemy to hurl. Okay, sure, there would be a fair argument to say that a kobold in spiked leather would be halfway, though I think the consensus would be that wouldn't quite cut it and would effectively be the same as the ordinary, run-of-the-mill leather armour.
But a goblin molotov cocktail, well, that's something else entirely. I'd be prepared to give that the standard 1d4+STR+1d6 for the alchemist fire. Potentially more for additional bottles. I mean, yeah, you'd have to roll for the chance that they'd break but I think the impact would be worth it. Especially since goblins are a race that are more likely than standard to come with bonus alchemist fire and similar products upon weapon selection.
No bards or gnome druids? Promise? I suppose we'll let the elven sorceress slide for now. After all, she is nice to look at and can be exceedingly diplomatic at times. That's always handy for a balanced party.
Seriously, though, I really do like the change in dynamic you get when you bring one of those classes to the party. It makes a pleasant change.