I am about mid game and the Sorc spells are still pretty clutch, though there is a scaling issue where the higher end spells do not do enough damage to compensate for their longer casting times and limited uses. Most of the tougher trash and bosses can be picked apart by rolling soul arrow spam. Undead Lords was basically a completely trivial fight and I one shotted it with no prior knowledge of the fight, as an example. Fights where the boss is super aggressive with some sort of leap/piercing attack are much more problematic. So, Pursuer, Medusa Bitch, and Old Dragon Rider were all tricky to solo. Without getting too laughed at, the one boss I cannot seem to drop is the Chariot thing, because the adds stun lock the fuck out of me if I remain stationary when the rape train circles around. That is also one of the early boss fights with the most brutal approaches to it, so keeping your mind focused on it is a little harder.
I began the game as a Deprived on my livingroom PS3, but rerolled on my bedroom PS3 as a sorcerer and found it infinitely easier. I was building the Deprived as more of a mele guy with magic to supplement and he was not really panning out, but I plan on respeccing faith with him once I beat the game with my Sorc. Anyhow, my build is something like: VIT18, STR14, DEX26, ATN25, INT32, and the rest base stats. I milked the Fire Sword for a good long while, but I am planning on building up Faith next for Hexes and lightning weapons, so I have a descently upgraded Heide Spear and Magic Mace as well. I like the Spear the best (hoplite 4life!) for a variety of reasons, but I generally use whatever element is most useful for the fight, otherwise. My next crafting project is going to be to work up a poisonous twin blade and a Dark pike. Biggest thing I have noticed in this time is that keeping the Encumbrance under 50% is critical, since poise is so meaningless and its important to move as fast as you can as a caster build.
And it sure seems like no invader is anything other than a twinked out mele build with _maybe_ one Pyro spell slotted. Basically, whenever I get invaded, I find a hard to reach spot, bust out the spear, and spam Soul Arrow when they get to me. Well, that or burn a seed and let them clear the zone trash for me for the Lulz.