Aside from the fact that they've never been classified as Micromasters, the Monster Pretenders are also larger than the Micromasters.
Your typical Micromaster is about 5cm tall whereas Monster Pretenders are about 6cm tall as robots, which is closer to the size of an Autobot Mini-Vehicle.
It would certainly match the size of Monstructor and Dino King as shown in canon.
And I think that the Pretender shells could be made as small accessories similar to the Prime Master "Decoys" seen in POTP. Or even just little solid unarticulated PVC figurines - you could call those Decoys too (in the same style as the G1 Decoys). They don't have to be working Pretenders. And then you could make a new set of Decoys for Dinoking at little cost.
Yeah, commercially speaking I'd say that Star Sabre is the most viable. Even for TakaraTOMY given that Star Sabre has been the [b]only[/i] non-Early G1 Transformer made as an MP (not including redecos), and that was a result of a fan poll too.
I would buy a CHUG Deathsaurus in a heartbeat! We already have RM and MP Star Sabre, but we don't have a post-G1 version of Deathsaurus (other than the redeco of Gigatron I think). They could easily work around the name thing like calling him "Darksaurus" or whatever (although Hasbro's gotten away with selling a toy called Death's Head, so... <shrug>).
On one hand I'm surprised that Titans Return Black Shadow was never redecoed as Thunderwing, but on the other hand I'm not surprised at all given how that toy shelfwarmed. :/
I wonder, again for commercial reasons, if it'd be more viable for Hasbro to sell this in the common market as Machine Wars Optimus Prime and then do Thunder Clash as something like a Pulse exclusive.
They could pre-tool it to be a shared design/mould with a CHUG BM Silverbolt.