I really hate the weird way the Lambo twins' arms are supposed to swivel up into the car hood, and I wasn't happy when they reused that bit of design for RTS Perceptor.
Mp megs. Rotf leader prime, i was stumped with him when i got him. The instructions were useless, had to resort to peaugh's video, thanks btw peaugh.
Skyhammer's Transformation is a receipt to get broken by kids. HA Bumblebee's chest is daftly designed. The protector armour is a minor pain to get back into trailer mode. Alternators Wheeljack is just annoying Alternity Bumblebee and Generations Scourge have a habit of getting stuck in mid transformation. Movie blackout's gears slip when you transform him meaning you need a screw driver handy to transform him. Both the ROTF Dlx and FAB Mudflap and skids are a bit annoying to transform due to tolerance issues.
RiD Skybyte for me. I'd imagine going from shark to bot would be easier then vice-versa. I do have to agree on RotF Jetire and MP Megs though.
i still have no idea if i'm transforming his feet back into robot mode correctly but. he stands [sorta] so i guess it works xD i think the only ones i really dread transforming are ROTF Jetfire ROTF Mixmaster [might be tough. I dont think i remember how to transform him so xD but i wouldnt say he's TERRIBLY hard] DOTM Sentinel Primes got some crazy feet. Takes me forever to get his panels and everything all lined up properly for vehicle mode MP Megatron can be finnicky if you dont know what you're doing. Its definitely best to take your time transforming that guy
I haven't bought too many larger figures so complexity isn't an issue but there are still some smaller figures that are a pain. HFTD Breacher, I'm not sure why but for such a small figure he has so many small bits that just won't fit, getting him into vehicle mode is harder than it should be for a simple figure. HFTD Ironhide, definitely the most trouble I've ever had with a figure, his whole chest just doesn't work and was the first case where i've had to go online to get help. Even now his chest doesn't really lock, one of the clips just pops out but now I'm positive that thats how its supposed to work anyway. I ended up being Cyberverse commander Ironhide to make up for it, who is an almost superior figure despite being way smaller.
DOTM leader Sentinel Prime...GOOD. GOD. I quite like complex transformations but that takes a long time to work with Sentinel! The panels, doors, and the top-roof take forever to peg, tab, allign -properly-, and stay together!
I think I did it once. Maybe twice when I did my video review. But I have not been able to transform Universe Hot Shot/Henkei Hot Rod without popping off the back kibble since. Universe Galvatron is just a piece of crap as well. I can never transform the arms or those tank pieces on his back without them coming off. And I'll say the Classics Seeker transformation is annoying only because I've got 28 of them on display. 7 of which I just opened and transformed to pose and display last week.
Classics Galvatron or any of the movie-verse panel-formers. But the winner is Alternators Dead End. I could never get the shoulders to rotate the right way to transform the arms back in.
HFTD Ironhide really pissed me off quite a bit. Got the robot mode fine once I figured out how to lock it all together, but a shoulder kept popping off while trying to jam him back into a truck. Not having tiny, tiny fingers, I had to undo everything to reattach it, accidently pop the shoulder off again, rinse, repeat, scream. I find DOTM Topspin's shoulder things irritating since they pop off every single time. It could just be mine, but it's constant.
You win. Leader Sentinel Prime. Those panels, those shell-legs, 'nuff said. Leader Jetfire. I used to think Leader Prime was hard.
This. ROTF is the King of all untransformable transformers. My only guilt in him is the poor factory workers who didn't get paid extra to put him together.