Creating *new* characters within the narrative or the original Transformers fiction really is a mixed bag. Some work, and some don't. My personal opinions don't really seem to conform to the norm,. but off the top of my head...
Sunstorm - Great character, (I'm a DW fan...sue me..
)
Drift - He's ok I guess, I'm pretty middle of the road when it comes to him
Windblade - not a fan at all, but I know I'm in the minority.
The Torchbearers/Victorion - They get an automatic
from be because they are a Combiner.
Slash - I really appreciate the look and design. She really does look as though she could fit in with the original 5 Dinobots. Since JP made Velociraptors overly famous, I'm not a fan of the jumping on of the fad, but I consider it a product of the times. I'd love to see more new Dinobots that have this aesthetic. I guess only time will tell.
I know there are a host of other new characters introduced by IDW comics that aren't toy tie-ins, but there really isn't one that stands out to me as absolutely great. I know they all have their fans, but most of them are quite forgettable to me.
Bucket/Want List: Botcon 2016 Customization Class Ratchet (G2 Deco), or Customization Class Ratchet (Marvel Comics Deco) **would also be willing to pay for an Unpainted Botcon 2016 Ratchet, TT Legends Fortress Head (only) with working Electronics
Wish List of Modern Combiners: Road Caesar, Monstructor & Dinoking (proper size to fiction), Landcross, Guard City, Battle Gaia, & G2 Defensor. Wish List of Titans:Metrotitan,Majin Zarak