Do you mean being able to layout the UI's? If so that's not going to be part of the application. We plan to make a quick and powerful editor but when you get into that area and want visuals your better off with an IDE that can support it.
Many of them have a delay due to it being the most accepted method for code completion, of course others are just because it can be slow :p. It is something we can look into.
Embeded SCM is something that I have been thinking about looking into as well.
Please make sure to submit these ideas to the forums on appgecko and I will start writing up the information for the Win32 GeckoPad (First version that will be released). I am still learning Cocoa hence why the win is the first target to have a beta :P.