I think it wasn't so much complaining that Geomotus wasn't Geosensus, as asking why they would resurrect the name and character just to change it, on the assumption they were related, then disagreements over whether they could in fact not be. If that had held any water, it would have been different IMO to insisting that the prose story guy inherently just needs a second pass right this instant. Like, the extreme comparison of this specific aspect of the disagreement (let's please no one get distracted by any of the others, the analogy isn't meant to fit them) would be IDW introducing a cowardly and disloyal leader of the Decepticons jets named Starbeam - no one would be talking about the IDW original character suddenly replacing the worthy Starscream, they'd be asking why Starscream was changed.
Everyone's always complaining now about how everything has to be G1, and now people are upset that Brian's making a new character and not using some rando whose sole defining trait was that he was a weirdo who got fridged.
That said I'm not sure what the overlap between fans who are regularly upset by too much G1 and ones regularly upset by IDW original characters is.