I feel the strengths of bitsy are that it is simple and accessible. Loading it with new features and placing it behind a paywall would negate both of its strengths. At that point I might as well look to something like GameMaker if I'm willing to pay, or Godot if I'm not.
If I were looking to purchase a cheap development environment in the spirit of bitsy, what I'd be looking for is probably more closely comparable to an even more streamlined RPG Maker. Features I'd be most interested in there would be something like:
- Dialogue trees with player dialogue choice cards (like the choices in RPG Maker)
- The ability to make dialogue choices appear only on variable conditions (more advanced than RPG Maker)
- The ability to change what sprites appear where, or if they do, based on variable conditions (like event pages in RPG Maker)
- The ability to lead from dialogue into a scene change
- The ability to send sprites on motion paths (like in RPG Maker) triggered by a dialogue
- Pushable sprites
- Sprites that can accept certain pushables as a key to annihilate both (to make locked doors)
- Sprites that can annihilate themselves based on player inventory or variable conditions (again, to make locked doors)
- Switch tiles that activate as long as a player or sprite is on top of it, and a condition allowing sprites to change if all of a certain type of switch are pressed.
Things like that. I'd also be more interested in something that lets me quickly make hobby games for HTML like bitsy does, since there are far more established professional tools, even free ones, if I were to look to publish on Steam.