I think what we're seeing in Lesson Zero is the episode-specific character quirks. Basically, different parts of the ponies' personalities are emphasized in different episodes for writing purposes.
Otherwise known as flanderization, a staple cop-out for mediocre comedy writing. You can't make a joke out of the situation you've put your characters in, so you inflate a trait or create something new entirely for the sake of a joke. This is a big immersion killer. Fine (in fact, probably great) for a series where you don't necessarily expect immersion; this is not one of those series.
Nobody got mad about Pinkie Pie and Rainbow Dash being prank-obsessed in Griffon the Brush Off, while not playing any pranks for the rest of season 1.
Oh they did, but they directed the anger at the meddling that caused it. The writers couldn't keep the EI tag without marginalizing their pranks.
Twilight is being more OCD than usual in Lesson Zero. Twilight was extra socially awkward in Look Before You Sleep.
Look Before You Sleep is actually an excellent example of good character writing... for Applejack and Rarity. The episode itself was... meh, but that's due to the setting (sleepovers aren't exactly the most interesting plots).
Concerning Twilight, that's a rather minor example and one I'm pretty forgiving to. If Lesson Zero were on a similar level (and honestly it probably would've been without the stupid crazy expressions), there would've been far, far less complaining. Sometimes you have to bend the rules a bit (nothing's
perfect afterall); the question is, do you get a net positive result from it?
Pinkie's Pinkie Sense doesn't appear in any episode but Feeling Pinkie Keen but nobody really cares about that.
Probably because most people try to forget that episode
It has its merits but the shoehorned and badly, badly worded moral killed it good.
I think people are just mad about Pinkie and Rarity because they haven't had an episode to themselves yet this season, so the few lines they have had are given extra scrutiny.
I'm in agreement here somewhat. Everyone has their favorite pony, and when they feel they're ignored...
My favorite pony has been very in character so far, so I'm not a victim of that (I really loved Applejack's reaction to Luna. Being quick to forget her fear and trust Twilight is so very, very Applejack).