The editor / engine is slowly getting new action parts / functions added to each new build to allow more flexibility without requiring Lua script. Most things can be achieved without scripting, however if you do want extended control & flexibility, then we do recommend you do at least learn the basics of Lua script.
It is technically possible to make other game genres although it might require more work than other engines as Visionaire Studio was designed with point & click adventure games in mind. The idea though is to eventually make Visionaire more flexible in terms of what type of games can be made with it. Platformer games (2D) mostly consist of tile based graphics which is something that VS has no support for.
Swimming, space walking & all that are theoretically possible. Just create a character outfit with character swimming or whatever it is that you want them to be doing. Unfortunately we don't have any physics in the engine, so if you want to apply gravity to your characters then you would need to write scripts / functions to handle it. The underwater visual effect would be possible by applying a ripple shader effect to the screen itself, which is as simple as copy/pasting the shader toolkit script into the script section of visionaire studio & then activating the ripple effect when needed by creating an execute a script action part containing the shaderAddEffect("ripple4") function.
I doubt the mobile / pro price will change. Everyone seems to think that other engines are so cheap, but it you bother reading the fine print then you will find out that they aren't really all that cheap. UDK has a license fee & then a royalties ( % ) of sales fee per game that makes over x amount. Unity requires you to purchase multiple licenses (per platform, not sure about per title). Game Maker Studio requires you to purchase multiple licenses (per platform) & so on. There's this old saying "if you want to make money, then you have to be willing to spend money". If you have no money, then try & find a job / save up. How most things work in life, no?
No idea about the turn before walking thing. In theory I suppose it could be implemented into the engine itself; so could sections for begin & end walk animations, but whether or not Alex decides if / when they should be implemented is entirely up to him.