Well, it does at least make a little bit of sense.
I mean, the big hype of Ravage in Season 2 was the idea that he was, like, the ONLY Decepticon given amnesty after the Great War, and reformatted into a Predacon to be used as the secret agent he was. And it was, of course, perfect for the end of the season and those episodes.
And Starscream and his immortal spark is freakin' terrifying, and a huge part of the reason why Rampage was, in turn, so terrifying.
I truly believe that the only reason Grimlock is on the scene is because Furman has a huge hard-on for him... which usually isn't a huge problem, but yes, I agree with you. I wonder how long before we see him in the reinvented G1. By the end of Devastation, you think? We know he's on Earth.
It makes sense that some G1 Transformers could still be around, but yeah, it should be rare. And well-explained. I mean, it should have a reason for being such. And, truthfully, I think that if it were just Beast Wars Americana, it wouldn't be needed or have been done, really. More or less.