I think some market investigation would help a lot.
Find out if the main objection is to the subscription model, and what would cancel that out.
The lack of having full features, and no guarantee of when or if they will be added, versus the price point at release.
Surely a lower yearly rate would sway some users.
Then for fairness, offered as a early adopters price as was done of C2.
An exclusive for existing users if there are any objections from Scirra.
Or just nuke em all, and start from scratch.
Hoping enough subscribers pop up out of the rubble.