I agree with this wholeheartedly. Or maybe even make a clean break and scrap OSA and introduce a new system.
I’ve been talking up the benefits of scripting apps on the Mac since the 1990′s. The sad fact of it is that Apple has never really supported scripting to the level that it deserves. It’s even more important now in the days of a UNIX based MacOS. I have a bunch of scripts that I rely on daily to help me get things done more efficiently. I’d write more of them, but two things hold me back. AppleScript is really a funky language. I’ve partially solved that by switching to using Python (via appscript) to do the scripting, but that’s only half the problem. The other half of the problem is that the API exposed via OSA is also pretty funky. If Apple cleaned all that up, in say, 10.6, I’d be happy to rework my existing body of scripts.
Even if that happened, the big problem is that developer’s don’t really support scripting that well, so a good scripting system overhaul needs to look at making it easy for developers to expose application functionality to scripts. Unless that part happens, improvements in the scripting language, and OSA’s API’s will not be enough to push scripting to the level where it belongs.