Well I dont know about the goto thing. I just think the idea is really cool. But whether you put all raw events in one code or seperate them into single events, I dont see a huge difference.
I dont know the working of mIRC completely, but if it loads all events you have written on start, so when its a raw 352, mIRC knows you have a "raw 352:*:" event and goes right to it, then I can understand it being better than it running through if's and elseif's to get to 352.
Otherwise, whether it looks through each raw event in a script or looks through each if and elseif till it matches ... seems to be the same to me.
