Everyone I know thinks 3.5 is frustrating compared to 4.0, and developing for 4.0 is no different than developing for 3.5, save for that 4.0 has quite a bit more functionality (awesome functionality, by the way) that isn't exactly required to get anything running.
Also, you are the last one on BYOND using 3.5.
Not by a long shot. I know quite a few people who still dislike BYOND 4.0 and several who got fairly upset when I mentioned possibly upgrading my game to it.
I have both versions of BYOND on my computer, and I honestly still prefer 3.5. Like I said, the issues with the macros, the blurring of maps and icons and the fact that a lot of new games don't have a proper interface set (thus meaning I have to basically setup my own one) are some of the reasons.
But look, and I'll say this to the other guys as well, I started this thread to ask about builder game source codes. I have no intention of holding a 3.5 vs 4.0 argument in here as well. If you want to discuss it, maybe someone can post a new thread about it. Either way, I've got what I need from here so I'll stop posting after this, unless there are questions related to my original post.
So yes, I need the building system. I'm not going to create my own building and map saving and loading system AND import a whole truckload of icons and the like just for the sake of testing an add-on.