The first level of Magaambyan Arcanist grants an Aura of Good. As I see it, that would qualify them for Sacred Summons. And by using the fist level of Halcyon Magic to get Summon Nature's Ally I onto your Wizard's spell list (and in his book), the Moonlight/Sunlight/Starlight Summons feats are opened up as well.
The feat tax to get into the PrC is unfortunate, but a Conjurer isn't really missing out on much by taking ten levels of Magaambyan Arcanist; instead of gaining 1/2 his level as extra duration on his summons, he'll gain his MA level as extra duration on all Good spells, which most of his summons will be, since he's going to be taking Summon Good Monster and summoning Celestial-templated creatures when he isn't bringing in proper [good] subtype outsiders anyhow.
So, is this idea bad/crazy/foolish for reasons that I'm not seeing?
Are the Sunlight/Moonlight/Starlight feats at all worthwhile? (I'm mostly seeing them as a way for summoned creatures to overcome nearly all DR.)
Is there any value to the Balanced Summoning Arcane Discovery? (It's interesting stylistically to bring in a CG and an LG creature, but since going down to a lower list can already bring in multiple creatures, I'm not so certain it's of any real use. Are there any mixed CG/LG pairs that would make an incredible team?)
You could get Superior Summoning instead and get 1d3+1 creatures of one level lower than your spell which sounds like a better bargain than exactly two. SS also works well with a metamagic rod of empower spell.
The Sunlight etc feats are not IMO worth getting even if you have spare feats. Which you won't have any time soon assuming you're going with Augment Summoning and the prereq feats for Magaambyan Arcanist, plus Summon Good Monster and maybe Superior Summoning. Which sounds like a good combo, don't get me wrong. But after them item creation and metamagic should be higher priority.
Well, the "benefit" of Balanced Summoning over Superior Summoning is that it is an Arcane Discovery rather than a feat. You get fewer Discoveries, but in a feat intensive character, saving the feat may be worth it.
And it lets you bring in two different creatures, unlike normally where you get multiples but must be the same creature. But I am not sure that there is a great use for it.
I think this is a really cool build in concept, but it takes a lot of levels and feats before you start getting to the heart of it.
Arcane Discoveries can be taken in place of normal feats, similar to Masterpieces.
True, but you cannot take a feat in place of an Arcane Discovery, which I think is what Samasboy1 was getting at.
Between meeting Magaambyan Arcanist prereqs and getting the core summoning feats, you'll gladly look at a mediocre arcane discovery that improves summoning. There's not much else you could have done with the 5th level ability anyway. Metamagic is bad as a summoning specialist and Fast Study is redundant since you get it for free as a Magaambyan Arcanist class feature, so the list of decent options is thin.
What? Arcane Discoveries are an optional thing from Ultimate Magic that can be taken in place of a Wizard's bonus or normal feats. They're basically Wizard-only feats. It doesn't make sense to talk about taking a feat instead of a discovery, because they're not something you get by default in the first place.
And the fifth level Wizard bonus feat would be getting used for Spell Mastery in this case. He'd get another Wizard bonus feat only at character level 20. I was thinking of possibly taking Balanced Summoning with a regular feat somewhere along the way if there was a particularly good use for it I wasn't seeing, but that seems unlikely.
OK, lets plan it out.
1: SF (Conjuration)
Human: Augment Summoning
3: Superior Summoning
Wizard 5: Spell Mastery
7: Sacred Summons (there are celestial creatures on the standard Summon Monster list which you can use)
9: Summon Good Monster
Wizard 10: Quicken Spell?
So the earliest you could get Sunlight etc. would be level 11. It might be an option then; OTOH if you want to beat DR then it might be an option to summon a huge fire elemental and burn them to death (substitute ice/lightning/etc as necessary), and it might be nice to get Greater Spell Focus (Conjuration) for non-summoning occasions.
avr, your suggestion is pretty close to what I was planning.
1:Spell Focus (Conjuration)
3:Summon Good Monster
I was considering Feral Speech to talk to the summons as well, but it's easy enough to add speak with animals to my spell list if I decide that it's necessary.
They'd be awesome as a single feat that lets you choose, either on during the casting, or even each day, to let your summons defeat one of the three DR types. But spread out over three feats, they're rather low-value, especially by the level at which you can obtain all three. At the very least, it'd be nice if Starlight's side effects weren't ruined by the light effect that both of the others give (not to mention two of them both giving the same light effect.) Given how much weaker SNA is compared to SM in Pathfinder, I'm surprised they didn't try to beef these feats up a bit to give the dedicated druidic summoner some love.