Yep, the HiDPI support would be nice for me as well, but it's something they're working on. Apparently it's easier to implement on Mac than Windows.
As for Adventure Creator, it's dead easy. Basically, if you follow those tutorials, you'll be able to do what you want. You can also use Playmaker with it, as well as any other Unity plugin. You don't NEED to program with it. Even for text-based things or dialogue, you can use the Adventure Creator UI to add that, but realistically and for ease of use, it does help if you bite the bullet and learn C#.
You don't have to go balls to the wall and learn it all as if you're programming some applications for Windows PCs. Just C# for Unity is good enough. Follow a few tutorials online, get the gist of it, and then go from there. Truthfully, there's probably a free script already written for what you'd want anyway online. So it's not like you really have to learn C# as if your life depended on it, unless you're wanting to become a developer for a studio.
ood to know! Gmscript looks pretty easy to understand, it's shame anything higher than that gives me sweats! I didn't realise it came with a built-in dialog editor, I though you needed a separate asset for that?