Runescape is less buggy, because its written in Java, and runs on a JVM, rather than a computer thats doing 20 other things at the same time. Incidentally, I'm a runescape member, (windofdsio) look me up
The big issue here, and the reason why EA's PC games have gone down the toilet, is that they are now making their games multi-platform, with the primary, and future focus more on consoles.
When you write software for a console, you don't have to worry about hardware variation, you don't have to worry about operation system variation, and you don't have to worry about other operations running in the background.
The console is essentially as close to that ideal environment that Java runs on as you can get, and its because of this that their PC games are going downhill.
BF2 in order to run, has to be running on an uncomprimised version of Windows XP, with no other programs running in the background. It needs to be able to dictate the exact hardware settings it wants, and to hell with what the driver has configured.
Its not designed to accept or allow any interference. That's why its a fussy little bitch of a program. Its because they have console coders writing the PC version.