And elemental based subclasses, and class abilities that, at first look, seem to favor blasting
I don't see any elemental sub-class.
There's Dragon, which makes you tougher and let's you fly.
There's Wild, which gives you all sorts of random effects, and some dice manipulation.
And there's Storm, which is probably the closest to blasting, but also includes wind and flying.
(empower, quicken, careful, twin).
Careful always seem like a control feature thing to me, and quicken and twin just seemed like a generic boost. Nothing about them says "blasting" about them, though they work just fine for that.
Empower is the only one that really says blasting. And yea, it's a little weak. Not a full trap, since it after the fact (thus you never waste it), and combining it with others, but still a bit weak overall.
Face value, to me, seems to say that blasting is only one of the things a sorcerer does.
Also, there's a lot of trap choices in the sorcerer class -- both in spell selection, meta-magic selection, and subclass selection. Picking black as your dragonblood color, for instance, is bad. Picking subtle is very limited except in certain game styles. Knowing that you should probably skip picking up a blasting spell of your color (provided your red or white) every level and instead up-cast lower level spell and pick up some variety is another.
I agree that dragon colors are a bit of a trap. But I still don't see how +1 AC, +1 HP, resistance, bonus damage to 1 element, and flying make it a blast-centric sub-class.
That said since it doesn't exist, there is plenty of room for an elemental blast-forced sorcerer sub-class.
1: Arcane Admixture: You can change the element (fire, cold, or lightning) of your spells.
6: Spell Shaper: You can change the shape of your fire, cold, or lightning spells, changing between cone, line, and sphere.
When you use Empower Spell metamagic, you can roll 1 additional die of the same type, and add it to the results.
14: Adaptive Immunity: You gain immunity to fire, cold, or lightning, depending on which spell you cast last.
18: ???