(new autobots)
Ultra Magnus: Michael Ironside
Override: Jane Leeves
Red Alert: Steve Buscemi
Vector Prime: Liam Neeson

(If they add beast wars characters)
Optimus Primal: Garry Chalk or Christian Bale (NOT USING THE BATMAN VOICE!)
Rattrap: Adam Sandler or Scott McNeil
Cheetor: Chris Pratt
Megatron (BW): David Kaye or Benedict Cumberbatch
Waspinator: Mark Hamil or Scott McNeil

(Decepticons)
Cyclonus: Corey Burton
Scourge: Christopher Walken
KSI Drones: Frank Welker
SoundBlaster: Daft Punk making random techno noises
Slipstream: Grey DeLisle

 

Grey Delisle would make a great Slipstream.

 

Adam Sandler as Rattrap. Please No.

That being said I can't help but be amused of the idea of Christopher Walken as Scourge.

 

I'd like to see Matt Smith as Bumblebee. Bumblebee is British in the movies, but Mark Ryan sounds too old. Besides, Matt Smith seems like he'd be perfect for the character.

 

It's a Beetle, I turn into a beetle now. Beetles are cool.
"Are you from another planet?" "Yeah"

We all change. When you think about it, we're all transforming, all through are lives.

 

Christopher Lloyd as Wheeljack, David Tennant as Skids, Kevin Conroy as Tarn (don't ask why trying to figure it out myself), Steve Blum as just about anyone, John Hurt as Alpha Trion or Vector Prime, Robert Downey Jr. as Brainstorm.or Nightbeat. Rob Paulsen, don't care who he plays but he's a really nice guy and I'm a sucker for Tmnt old and new, Catherine Tate as somebody not too many fembots to choose from so hard to say, Freema Agyeman as Windblade, Emily Mortimer as Nautica, Kelly Macdonald, Martin Freeman as Thundercracker and John DiMaggio as Seaspray.

 

HOLY REDDINGTON BATMAN I NEED TO SEE THIS YESTERDAY

I can definitely hear it, but I'd much rather see Matt Smith play a villain. His "Mr. Clever" in that Cyberman episode was absolutely stunning. I think he'd make a deliciously psychotic Star Saber.

I've always imagined Benedict Cumberbatch as Obsidian, but I think now I'd like to hear him as Tarn (seriously) or Nightbeat (for laughs).

John Goodman needs to stay on as Hound. I loved every second of him in Age of Extinction. He stole the show.

Oh, and John Simm as Overlord, since he's supposed to sound like the Master.

 

Overlord's supposed to sound like John Simm? Time to re read every comic he's in then.
Also now you mention is a Mr Clever sounding villain would be great.

 

I've always imagined Ewan McGregor as Movie Bumblebee if he actually got a proper voice.

 

Mine would have either Peter Cullen or Dr Smoov in it

 

I'd like Brian Denis Cox as someone, I don't know who. Galvatron would be nice.

https://www.youtube.com/watch?v=rNAnplKWNrc
https://www.youtube.com/watch?v=3mPYW9F00uA
https://www.youtube.com/watch?v=jiIaX4_pmpY

 

Chris Pratt would be awesome as Bumblebee, Someone from New Jersey as Wheeljack(Bobby Cannavale maybe), Jessica Biel as Arcee would be awesome

 

Also, Paul Bettany as Shockwave would be really cool

 

Chris Pratt would be a good fit Bumblebee and Paul Bettany as Shockwave. I could dig that.

 

I want to see that even more now.  

 

Benedict Cumberbatch as Megatron.

 

Nah, not for me.

 

Cumberbatch is Shockwave material.

I'd like a reboot Megatron be Clancy Brown or Miguel Ferrer.

 

It may sound crazy but how about the guy who plays Storm Shadow in Retaliation play Drift