Rich:
If you keep the pictures simple, making them won't be any different from making AGI pictures--they'll just be drawn at a 320x200 ratio rather than 160x200. Since you draw in a 320x200 resolution in picedit, it'll be just like that, just less blocky.
The graphics aren't a huge deal. It won't matter if you keep them simple. Once you start drawing your pictures in SCI Studio, I doubt you'll want to go back to AGI and the DOS picedit.
As for the scripting, it is more complex than AGI, but with my tutorial, it should be no harder to learn. I'm making it as easy to understand as possible.
SCI gives you far more abilities than AGI, so once you learn it, I doubt you'll want to go back.