I'm not sure sure if an Eternian Playset would be more feasible than Castle Greyskull, but the suggestion has merit.
It would give a little bit of Greyskull and a little bit of Snake Mountain at the same time. Seperate releases for each tower would be COT (cash-over-time) damge instead of a single burst of cash damage.
Would there actually be more parts sculpted and painted and cast for three towers than for one Castle Greyskull thus raising costs? Is there a greater demand for a Classics Eternia Playset than for Castle Greyskull?
In the end, I'd be fine with either...on one condition. I don't need a playset. I'm a big advocate of to scale 2-sided display sculpted dioramas that use hinges and no electronics, springs, or levers. That with some releases of diorama accents like the Weapons Rack and the Greyskull Orb Holder (which I must have...damn exclusives). For me that would help keep costs down.
I have the same desires for Snake Mountain, Fright Zone, Eternian Towers, and even if we got one the Crystal Castle. I know that I am not going to play these so I don't need any playset features. Just 1-3 levels of figure placement, a few hinges so things move, 2-sides (interior/exterior), and a moderate to moderately-high price point.