No. Overlord was, by all indications, not intended for the US market. As is, he only appeared in the European market as a result of line’s unexpected popularity surge after the the brand was shuttered for the US market.
Well, that's how things shook out (and Skyquake, a later European exclusive, would likely have gone to Japan if their G1 line wasn't in its death throes after "Return of Convoy"). A TV series holding its own against second-wave action cartoons such as TMNT might have meant more investment by Hasbro, and
possibly more shared concepts (though considering that Toei-G1 seemed determined to do Its Own Thing with Masterforce, that's not a guarantee. Even with a shared English-language market, Thunderwing and Bludgeon weren't particularly pushed as Big Bads until Furman came along....)
We can't be 100% sure either way without a Multiversal Galaxer, is what I'm saying.
My feeling was that, over the course of the unproduced fourth season, Galvatron would have become increasingly marginalized in favor of Scorponok.
Probably also an increased focus on Nebulos away from Earth, as well, which would ease a "rotating out" of veteran characters without resorting to obvious death-clearances. Here to one can compare and contrast with Toei's The Headmasters (as by 1987 Japanese animation was largely priced out of most US production budgets, it probably would still be a divergent storyline, though perhaps slightly less so than what we got).
Given the typical television “season”, the fourth season would have likely featured the appearances of some 1988 toys early (The Seacons, Cassettes and Quickswitch are most likely, IMO).
Yes, as the Combaticons were third-wave product showcased in late Season 2, and the Terrorcons were fourth-wave product introduced in Season 3, it stands to reason that the Seacons would likely have seen a mid-to-late Season 4 debut. Though without a clear rival to Piranhaking/Kingu Posaiden in the production we got, speculation can only run rampant at this point.
There's the next question, who should be the rival to the Seacons?
The hypothetical 5th Season would have started with the introduction of Pretenders and Powermasters. Scorponok would have continued as the “big bad”, likely supplemented by the Decepticon Powermasters and Doubledealer as “core villains”. By the end of the season, we’d have likely seen the initial appearances of the Micromasters and possibly the appearance of the Classic Pretenders, or at least the characters planned to be so (which likely would have made Starscream a dominant villain).
And once he's back, all bets are off plot wise....
