I mean when a character was first shown in the movie and/or when a 'bot or 'con first transformed
For me it was when Soundwave revealed himself to be carly's car and when shockwave first appeared

 

My fav is probably the Megatron introduction scene with the three main Cons in Africa. Megs' transformation was awesome, and it was cool to see Soundwave in bot mode for the first time along with Laserbeak.

 

I really liked the whole Africa scene. Dino's first transformation was pretty cool too.

 

i liked seeing Starscream land and sarcastically say how he hates seeing his "master" so weak and powerless while in Africa. and Igor. Igor was funny as hell.

 

Probably Shockwave for me - the way he arose from that swirling mess of metal. Though I was disappointed that it amounted to nothing and that there was zero explanation as to how/why he had a giant pet snake that can apparently travel from Russia to Chicago in a day and does whatever he wants it to, or who he is in terms of Decepticon rank/importance.

Same thing with the Wreckers. They're just there. No reason or explanation whatsoever as to where they came from or why they're armed-to-the-teeth stock race cars of all things.

Soundwave was just confusing. Somewhere between movies he changed from a large satellite to a small Mercedes luxury car. Okee.

Would have also been nice to know why Megatron was in Africa, why he finally took on an Earth alt mode, why he chose the alt mode he did, how Starscream, Megatron & Soundwave managed to pop back over to America from Africa in the blink of an eye, how Laserbeak managed to travel the globe within what felt like mere hours, why Autobots like BB, Sideswipe, etc. can suddenly turn into moving war machines (aka the whole Mech Tech gimmick), where Prime's new trailer came from, where the Autobots own fancy new space shuttle came from that lets them shoot on over to the moon on a moments notice, why Sentinel already had a super modern Earth mode body while in stasis lock on the moon, where Brains came from and why he lives with Sam & Wheelie, why many of the Autobots look different (just like why Starscream was suddenly sporting new tattoos from TF1 to TF2), where Dino & Que came from, what happened to Skids & Mudflap aka the two main bot characters of the entire second movie, who & what Igor was, who & what the Dreads were, etc... but I suppose that's just being nitpicky.
/sarcasm

Back on topic, I also liked Dino's first reveal. Very fast & switchblade like.

 

This one. I didn't see it coming.

 

Shockwave actually had a pretty damn cool introduction. With all of the other bots, it was like "Oh yeah, they've always been here. Didn't you know that?". Shockwave made damn well sure that he had a grand entrance.

 

Nipticky, much? I can give you some of that, but some are very farfetched.

 

Carly, the firs time we see her walking up the steps in 3D....

Oh, the robots you mean, I would go for Shockwave was good and the Wreckers introduction and how they were referred to as "a*-holes" I laughed at.

 

Yeah, I liked when Shockwave rose from the drill worm. Unfortunately thats about all he did.

 

The "Dreads" on the highway scene. Love it.

 

Dude totally agree with you Carly was hot and way better than Megan

 

Probably Dino or the Wreckers. Which brings up a point I've been wondering. In the movie, they say that that ship to take them away was how the second wave of Autobots arrived. But who would be considered the second wave?

 

Dino,que,the wreckers

 

Wrong. Sideswipe, Jolt, The Twins, The Sisters, The Wreckers.

 

i liked how when we first see wheeljack, he is handing out inventions.  

 

How? The Wreckers weren't in TF2, so you can't really consider them to be with Sideswipe's group. Mearing might have meant the second wave of newcomers to add to the original 5 Autobots from the first movie.

Besides, if we classify Autobot waves by their arrivals on Earth, wouldn't it be

Wave 1: Bumblebee
Wave 2: Optimus, Jazz, Ironhide, Ratchet
Wave 3: Sideswipe, Arcees, Twins, Jolt
Wave 4: Wreckers, Dino, Que, Brains

 

Mirage, Sideswipe, Bumblebee and Wheeljack (I think) in Iraq.

 

The Wreckers came with Sideswipe, they just weren't let off of the base and we weren't informed about them in ROTF if I understand it correctly.

 

Didn't they say in the movie they arrived with the rest of the new autobots but volunteered to build the spaceship?