Until the favored soul pass comes I'd go cleric. I think casting cleric is clearly better (atleast in heroics) right now because of the divine disciple tree. Favored souls don't get any SLAs.
If you want a caster, build a standard 20 cleric caster. Off the top of my head feats will consist of spell focus, greater spell focus of either necro or evocation. Also take heighten, quicken, maximize, empower, and empower heal. Max WIS at 18 and then take a decent CHA around 10-12 and CON around 14-16. Go human for sure on a pure. The extra feat is critical.
Invest a lot into the divine disciple tree, apply your metamagics to the SLAs and cast away. Take stuff you can apply to metamagics as soon as you can.
If you want to go with a melee cleric check out my melee cleric build here -
https://www.ddo.com/forums/showthrea...e-Cleric-Build
You could build the character the same but run in Sentinel instead of Dreadnaught/Crusader if you wish to be a tank.
Both caster and melee cleric are very viable, just depends if you prefer to be an upfront melee or backline caster. Pick one or the other and specialize in it.