Once you get around level 26 for a 0/17/0 spec, PVE becomes effortless. The idea being:
Shield Qyzen. Start with a Force Wave while he's going in. Kill stuff.
The idea here is Telekenetic Effusion = limitless mana. Also at 32 you get Force Quake, making PVE even easier.
Go TK and focus on questing/PVE and you'll do great. Higher levels a TK/Balance spec becomes great too.
MMORPG Perspective: Sages are probably the best solo PVE classes in SWTOR. The combination of control, heals, shields, and great DPS put us in the legendary MMORPG solo PVE club such as EQ1's Necromancer, WOWs Warlock / Mage, and DAOC's Enchanter.