I have to say that there are some frustrating aspects to working with c2 (performance of html5 when wrapped on most mobiles, limited physics engine - these are my least favorite aspects of the engine). However, the editor is fantastic and, if you don't have the time or aptitude to learn to write in a programming language, c2 is empowering. I don't accept your point about it maybe being a toy - a phrase about workmen and tools comes to mind.
So, I take it from your post that you are concerned about webstorage being deprecated? Why not just copy the webstorage plugin, keep it safe and, if necessary, re-add it to c2 if scirra decide to remove it completely?
As I understand it, the webstorage plugin was deprecated only because the chrome store no longer permits the use of that api - so blaming scirra for its removal is somewhat misguided. If you're selling on the google store - exporting for android - how many of your players are really going to care if their local-to-their-phone high score is removed by an update to your free-to-play game? See the point about copying the webstorage plugin if you think it's really a problem...