I only use maximize and empower for SLAs, (which I'm going to drop if I commit to pushing for DCs, so that solves one problem), radiant burst (no aura), and two direct damage spells, to wit blade barrier and divine punishment. Out of these only the latter spells increase my mana costs, and I usually only have to drop a few blade barriers per quest while divine punishment is reserved for bosses. Here's a list of feats I would ideally want:
Spell Penetration + Greater Spell Penetration
Spell Focus + Greater Spell Focus: Necromancy
Since I'm only going to get 7 heroic feats and I presumably want to take epic feats as my, well, epic feats (epic spell focus and penetration, and probably an extra point of wisdom*), I'm going to have to drop two of those. Now out of those, and with the goal of DCs in mind and the need for heals, I feel like maximize and empower are the odd ones out. This is going to be a big deal for boss DPS in a party (DP) and trash DPS on my own (BB); an even bigger deal than I thought, in fact, since I was somehow under the impression that maximize added 100 spell power and not 150 as you pointed out.
On the topic of stats, I completely blacked out on taking 6 points of wisdom in my ED. All things being equal, with my current gear (which admittedly leaves room for improvement as I've already pointed out), that would take me to 48.
* I guess giving up on epic spell penetration and epic wisdom would allow me to fit in everything on that list, I'd just have to take two heroic feats at epic levels. Talk about being a late bloomer.