Insectoid doesn't really make them a hive mind. They displayed individual consciousness during the fight - They were fooled by RD and Fluttershy, and exasperated by Pinkie Pie. Plus they have rankings beyond queen/soldier(At least one of the changelings shown on-screen looks like a captain). They also likely wouldn't look ugly to themselves, as it would make it hard to mate. Besides, they seem to be largely endoskeletal(The mamalian mouth and teeth, the 'soft' looking ears and possibly tail, not to mention Chrysalis's mane), so they probably aren't as insectoid as they seem. For all we know those weren't even their true forms, just something adopted to intimidate.

Their true form is actually really,
really attractive.
Mr. Blue, you did it right
I know I've seen one when I was doing one of my picdumps, but I didn't bother to save it.
Mr. Blue, you did it right
No. You want it, you go find it. It's on Ponibooru somewhere. G'wan, git!
Mr. Blue, you did it right
Why exactly are we assuming that the changelings are perpetually in a form other than their natural one? Wouldn't it make more sense for them to be in their natural form most of the time and only change form when it benefits them? I seriously doubt that Chrysalis keeps up her Cadence form when she's just lounging around the house. Even the drones only took on pony forms for strategic reasons.
During S2 cloning become smaller and smaller (or I just imagnining it?)

Changeling started regrouping into army from last episode).
Because he know I'm going to go out in this plane and I'm going to remove one of His creations from His universe.
I've seen a couple FEED!. I wanna an OBEY!
Does that make him... Captain of the
Blackguard?
Mr. Blue, you did it right
@Keg: I think that's assuming a bit much about how their feeding cycle works, but it does make sense. I'm not quite sure that they need to be in disguise to feed; if they did it wouldn't have attacked Canterlot in their native forms.
Yeah, but it's stated in episode that they imitate a pony and feed off the love given to them by the loved ones of the pony they're impersonating. I still hold that attacking Canterlot was only to cause chaos so that they could transform and slip into their hosts lives.
Hmm, but she yelled out "feed!" when she sent them to attack.
Mental image: In the scramble, a couple gets separated. Let's call them Aerith and Bob. They both encounter a changeling disguised as the other. More chaos ensues, everyone gets separated again, except Aerith and Bob find each other for real this time. the disguised changelings also find each other, but since both are still in disguise, neither of them realizes the other is just another changeling.
Mr. Blue, you did it right