I've thought up a few things over time, and I've heard words about a 'assortment of comments made about Summoner that are collect somewhere', but don't know where this where is!
So, until I find that place to see if other answers are there..here are some questions or curiosities I have, to see what others thing, and so they're out there for answering in a more official capacity.
1) Antimagic fields
The norm of such fields is that summoned creatures 'wink out' until the effect is gone, durations still apply, but the key issue here is thus: does the Eidolon wink out too? Naturally, it has a permanent duration, so it won't run out of time, but It would suck for it to suddenly vanish on you - it also makes the text under flight redundant when you get supernatural flight (it can't fly if it's not there, right?)
2) Eidolon summoning wording
I understand the class is in playtest, so this may be draft wording oopsie than a 'critical error', but by the way the pdf words Summoning your Eidolon, so long as it doesn't get dismissed due to 'death' (via hp loss) You can technically call it back repeatedly in the same day. It only gets full HP once (from the initial summoning) but otherwise, until that one death, you can keep calling it back. True, False? Unsure? I'd feel better knowing a need to dismiss my Eidolon won't screw me over for the rest of the day.
3) Durations after death/otherwise?
This involves summon spells and Eidolons. I don't recall...but will a summoned creature continue after its master bites it or falls unconscious? Does the Eidolon? Heck, if the Summoner dies, and the Eidolon has access to a proper resurrection spell (via various means, such as wishes), and has the necessary components nearby to use, could the Eidolon revive his own Summoner? That'd be pretty friggin sweet, to be honest. Summoner falls, Eidolon swoops in, grabs body, and takes it off to be brought back to life while it still can.
(The only flaw in that plan I can see is the range distance factor. If you're dead, you may not count as being 'there', heh).
4) Transmogrify spell
It doesn't exist to my knowledge, so it must be in the upcoming book. Any minor hints of what it is meant to do? Just a way for players to 'alter' their characters in a more magical way versus IC/OOC 'retraining'? What's to really stop you from using the retraining answer for Eidolons, apart from the current text saying 'they're stuck that way until you level, or use Transmogrify'?
That's all I can think of questions-wise for now. gonna see about a lvl 5 summoner playtest.
EDIT:
Silly me, I forgot part 3 of my confessions...err, forgot a tidbit I considered for the magical items issue.
1) Let the darn equipment go with the Eidolon. So long as they're wearing it or actively carrying it (such as a backpack) Why not? If you're smart, you'll use it in spiffy ways, if not, it won't get used. It saves dealing with some work in some cases, and makes small Eidolons sneaking into places, grabbing loot, and being dismissed a viable use. Living 'equipment' (aka kidnapping halflings, you horrible person) can be excluded. That means cursed gear will stay stuck as needed, and other magical gear doesn't have to be picked up or salvaged from the bottom of rivers.
2) Make it so the Summoner can wear the magic item, and bestow the benefit to the Eidolon by proxy. Whether or not they get the boon too is up for debate, but it would make the issue of item slots moot (since most summoners will have them all), and you don't have to worry about adding feet to your fire-breathing ball of slime to use boots.