This is interesting: do you also allow them multiple attempts? I like to play that with aid another, you're foregoing the multiple attempts, but it's never very clear. I'd be interested to to hear about your experiences.
I'm not TwoSix, but just to add to the sample, what I've noticed my players do is, if any of them think the DC is remotely possible, they all have a go separately, because they're instinctively worked out that the odds of one of them succeeding that way tend to be a fair bit better than if they actually use Aid Another, which requires a successful (if every easy) check to grant +2 to someone who might get a terrible roll anyway.
If they don't think the DC is possible for someone untrained or with a weak skill, then anyone who can will use Aid Another on whatever PC has the highest skill.
It's pretty reliable. Like you I feel there's some ambiguity over Aid Another vs Multiple Attempts, but I don't typically allow multiple attempts unless there's a clear reason to (like, trying to climb something or whatever). I notice that players who roll Aid Another typically do not also attempt to then roll for themselves, but it's not a hard rule, afaik.
Gotta agree with those who hope Detect Magic is something more impressive than the usual Detect Magic if it's actually a first-level spell. I really really do not want to go back to 2E days on that, especially as the problem of having to memorize Detect Magic (or use spell slots on it, as it would be in 5E) was solved by lots and lots and lots of scrolls of Detect Magic, generally. I never saw it make the game more interesting, only slightly more irksome.