Definitely a purchase for me, but even not having the original Grand Carousel I don't think this one was or is meant to compete? This does look smaller in scale - none the less I will be happy with it.
^ Is the new part significantly different to the old? Is the reinforced underside preventing some connections?
No difference from the outside.
Here's an image showing the detail:
I can't think of any 'legal' connection that would be prevented by the reinforced underside.
Could have been 25 years before the first molded torso, perhaps? Not sure if we have a date on when Sea-Tron was in development, but the first molded torso (apart from "stiffy" figs) I believe was in 2012 for Ninjago?
the one you put on top of a regular torso?
has there been a modified torso that fits on legs?
and the head? I think I read yoda or jar jar were first to have modified heads, but I don't know.