To the OP:
I run a pure Wiz PM.
I rarely ever run out of sp. I go lich form and gear towards neg spell power 1st, and neg healing amp 2nd. I always max my heal skill and once I hit level 12 it's easy street. By the time I hit level 15, I blaze thru GH and usually solo the whole saga on R1. Most mobs I 1 shot with Necrotic blast which costs only a mere handful of spell points. The few mobs that are immune to Neg energy, I usually hit them with chain lightning, arcane tempest, or wall of fire. I deal with undead by blasting them with Necrotic blast from a distance when they are at full health, then, thanks to Unholy Avatar, The next blast usually takes about 65-75% of their health and I jump back and hit them with one more and the whole group is annihilated.
At epic levels around level 26, I take the Draconic Incarnation enhancements to turn all my spells into Negative energy DOTS and then modify my epic strike to explode within - again easy street, hit the mobs with necrotic blast, and if they don't die before they get to you, explode with the epic strike and all are toast. With the Necrotic blast, I usually hit at least 3-4 monsters and they get 5 ticks of 2-3k. Hit them with chain lighting, they get an additional 5 ticks that stack on top of the first lot...
Usually never have to use a shrine, and most definitely don't run out of spell points. Never have a problem taking out mobs and rarely I use instakill.