Here's a guide to playing blasty castys. It's written with wizards in mind, but much of it will be useful to a cleric as well.
As to which is better, control or blaster, all I can say is play what makes you happy. Control is probably stronger, but you don't play the game to kill creatures of appropriate CR as efficiently as possible. You play the game to pretend to be a character who does cool things, and if throwing fireballs is a cool thing you want to do, more power to you.
If I wanted to play a blasty sorcerer/cleric, here's what I'd go with:
Human Sorcerer (Crossblooded (Acid, Draconic (Black)), Tattooed Sorcerer) 1, Cleric (unarchetyped, maybe Theologian, more on that later) X
(I'd take the Sorcerer level first, and then go into Cleric.)
Str 7
Dex 8
Con 14
Int 13
Wis 19
Cha 14
(on a 20 point buy)
Traits: Magical Lineage (Fireball), Reactionary
Feats:
1- Spell Focus, Spell Specialization, Varisian Tattoo
3- Improved Initiative
5- Intensify Spell
7- Quick Channel
9- Empower Spell
11- Divine Interference
13- Quicken Spell
Now, here's my reasoning behind all the decisions, starting from the top. Taking the Tatooed Sorcerer is a no-brainer, it swaps out your first level ability (and neither claws nor elemental rays mean much to you) for a familiar, which can intimidate or UMD. It also swaps out Eschew Materials (a pointless feat made more pointless by the fact that starting at second level you're never casting another Sorcerer spell) for Varisian Tattoo, which is a feat I can get behind.
As for not taking an archetype for Cleric, here's why. Variant Channeling. If you have the Magic domain and you're using it's variant channeling option, channeling to heal will give you +1/2 your Cleric level (rounded up) to caster level checks. This'll let you punch through SR like it doesn't exist, and if you use it before casting dispel magic there's no way you'll fail. With Quick Channel it's a move action to use, though mind your uses of it as it's a time a day thing.
If you go Theologin, you only get one domain, which'll be fire. In return, you can intensify your fireballs for free . . . which isn't a weak ability at all, as you'll be intensifying them eventually anyway. If you decide to go Theologin instead, you won't need as much Cha, so you'll likely be editing the pointbuy. You'll also free up two feats in Quick Channel and Intensify Spell (but might have to spend them on Spell Penetration and Improved Spell Penetration). So, there's definately a case for archetyped and unarchtyped. The choice is up to you.
One archetype you'll notice I did not even consider is Eccleasiturge. The reason for this is that it swaps out your biggest strength over wizardkind (casting in heavy armor with a shield) and trades it for jack squat. Speaking of armor, you'll notice I didn't spend any feats on heavy armor proficiency. That's because you never plan to use attack rolls, so you might as well wear armor you aren't proficient with and eat the ACP to hit. I recommend using a tower shield as well, keep them enchanted up to par and you'll be nigh unhittable.
In any case, that's my advice, take it or leave it. Whatever you do, I hope you enjoy it!
Er, maybe I'm missing something, but can't you prepare off-Cleric-list domain spells only in your domain slots? Doesn't that mean you can only cast one Fireball per spell level and day?
Theologian overrides that, but the unarchetyped version doesn't seem to work.
Theologian overrides that, but the unarchetyped version doesn't seem to work.
Urk! The original intent was to use Preferred Spell, but somehow the feat and it's prerequisite didn't make it into the listed feats. Major brain fart on my part.
Theologian looks more and more appealing, I'd probably go archetyped.