Of course scripting will be available- in fact, more powerful than VX. We're using BriskVM for the scripting language.
There are tools available to scripters- the built in script editor, "plugin" support which allows mods to the editor itself, is object-oriented in nature, syntax highlighting, and script import/export options. And it's better organized.
Horizontal staircase- this will most definately be addressed. Thank you so much for the recommendation, we'll try to have it in the stock tilesets.
On the fly editing- basic map editing, *possibly*. There will be a script console, similar to the same function in BethesdaSoft's Morrowind and Oblivion. There will also be several debugging options not present in RMXP. For example, fast forward and slow motion (increase/decrease framerate), live party editor, and item handling debug menus, among others.
We are making every effort to support a widescale, powerful system. I'm trying to bring special FX via OpenGL or DirectX; this is not a definite, or even a probably. It's an "I'm trying", and a quite possible fail. But if we get motion blur and whatnot, it will be truely like Christmas :D Screen transitions were implemented earlier today, and we're working to expand beyond what RMXP offers, into fully scripted transitions (although simple "custom fade" transitions will still be doable.
Progress is steady. We have a working map editor, tileset support (going for multiple file support) and a configurable party. Tis' only the beginning.
Edit: As for the source code, this will be more of a holy grail. By charging for the program, our development staff (english, by the way) will be spending a lot of dedicated time. And even the hidden classes and methods will have full documentation available. And if someone were to demonstrate a good knowledge of the program, and willingness to play nice in the forums, we'd be glad to bring them aboard and let them sift throught the estimates 22,000 lines of source code that bring you RPGA.
Edit 2: An apology to vgvgf and Alexander Morou. vgvgf, this project is in no way .rxdata related and should not detract from your project. Not trying to steal your show. And to AM, I have financial records from January of this year related to the development of this project, and it is in no way attempting to detract from your contest. I fully support your project/contest, and hope this won't offend you in any way.
Edit 3: Not sure, but I don't think it's possible to add a poll to an existing topic. For character templates, would you like to see merely human, or more "race variety" like in the Elder Scrolls series? (Human, Elf, Orc, Catperson, etc.) The character development process is generation, not premade characters like in RMXP. If you would like to see races, either reply or PM me, and let me know what races you would like to see. No need to mention the standard Human, Elf, Halfling, Orc, Catperson (pending effective name) or gerbils.
Also, to Tdata, In/Out templates: probably not. An effective and open-ended vehicle system, however, quite possibly.