To answer your original question, I will say this: The new necromancy and summon feats are very cool, and I like that efforts were made to shore-up the weaker side of magic on this server. They provide a lot of RP potential and if you want to take them, there's nothing wrong with that.
However, they're not the "optimal" path for casters and you're going to be worse off than casters who did not focus on the summon feats (in my own opinion). The short duration of the summon means that you're using not only the summon spell, but many other "buff" spells, for something that just isn't going to last long. In a dungeon, it's basically only useful as a distraction against equal-level content. In PvP, I could see them being useful in the lower level ranges but only if you buffed them first and even then, probably only against non-fighter types.
For example, int he case of Animate dead: It's not just casting a level 5 spell to summon a monster to attack something. It's a level 5 spell, and then bulls, cats, bears, gmw, haste, flame weapon, iron bones, mage armor, shield. That's 10 spells total for something that is lasting 1 Turn + 1 round/level. So a companion that, as a level 10 wizard, will last you exactly 2 real life minutes. Extended, that's 4 real life minutes. So at level 10, extended, you're not even looking at a single ingame hour tick. At level 20, extended, you're looking at exactly 1 ingame hour tick, and by level 20 the undead series of summons are pretty underpowered for anything you might want to do. Now I understand that the counter philosophy is just "Well don't waste 9 buff spells on it, stupid" and obviously, that is an option if you want to try that or save spells. But anyone who has tried to use the summons against equal level content knows why you need to buff it.
All that being said, I say go for what makes you happy RP-wise first and foremost. If you want to be a necromancer who is often summoning undead, take the feats and try to keep your summons in flanking position where they won't get insta-killed by mobs. If you want to only occasionally make use of undead companions, you could also consider Control Undead (circle 6 for clerics, 7 for wiz/sorc) which is 1 turn/level by comparison. That's plenty of time to buff something up and actually get use out of it, but you have to go out and find the enemy you want rather than summoning it which is the drawback. If you're just doing it as a cool RP flavor thing, you could always build for something else but still summon the undead for scenes or intimidation or whatever the case may be.
