I would pretty much like to see a Part Grass/Fire Type for once. It would make up for all of Fire-Type's weaknesses, and they could combine a good attacker with a good defender. That would make it a worthwhile starter despite evolving into one of the other Types of starter Pokemon that you could pick. Plus it's only weaknesses would be Flying, Ground (But the Grass-Type combo makes it render Ground pretty much useless) and Poison, which most aren't commonly used in Pokemon Battles anyway, except for the popular Crobat (Still, ONE of the new Starter's Defenses must be good, in fact it will be best to have a great Defense). Plus, since it is a Fire-Type, it's not impossible for it to learn Dragon-Type moves, which completely removes the Dragon-Type problem. Plus, many Grass-Types can learn Rock and Ground Type moves, which is super effective against all of it's weaknesses (Not counting Ground, as that would already be sorted with Grass-Type moves).
What I said above may make a h*ck of a good Fire Starter.