Buzzsaw - hardly ever featured in the cartoon,what about
Frenzy, - might be the name given the Soundwave character in the new movie - I'm "wait and see" with Frenzy. Because he's small, that's what prompted me to look at Lugnutz. But I'm buying a whole Honda to represent Rumble, so I may as well forget about having any Decepticons that are smaller unless there's a really cool Soundwave movie figure coming.
Kickback, Shrapnel, Bombshell - it's hard to say why futuristic, large and deadly robots, would disguise themselves as giant insects. They should have been the size of real insects and not really indulged the whole "size change thing." For espionage, I'd understand Insecticons. Wheeljack's excuse for the Dinobots was better.
Reflector, - was very cool. I'd like to see him again. But he'd need to be microscopic to be onscale with the Alternator line.
Scrapper, Scavenger, Hook, Mixmaster, Long Haul, Bonecrusher, - they should each be pretty huge - almost MPEs unto each individual themselves. Devastator could still be formed, but he'd be huge - we're talking a 24" robot, minimally! If they make a MPE Grimlock though, imagine how the two of them locked in combat would look! Oh - and I'd change the color to a more realistic "construction yellow and construction orange, with maybe MixMaster in white or something." It wouldn't make a uniform or pretty Devastator, but it might make him downright frightening!
Blitzwing, and Astrotrain - Blitzwing could be done as a MPE - but he'd need to Triple-Change. That'd be the best MPE right there!
Astrotrain would need to be at least the size of the Queen's Royal Starship to really work on a level I'd like to see him at. To form the train, he'd have to wrap up tight with no room for passengers. The shuttle could transport other Alternators or MPE's though (possibly). His robot would end up being very bulky and awkward, I think. I'd be really careful about expressing my desires for Astrotrain because I'm not likely to buy what they could cost-effectively wind up producing.