I have to preface my statements by saying I've never downloaded a mission, ever. I've only played my own and the BIS/Red Hammer missions.
However, I think addons really make a mission. I haven't made a mission without a 3d party addon in fact. I can't stand most of the BIS models. So bad in fact that I can't get past them and enjoy a mission (obviously I don't play the canned missions much!
).
There are so many weapons not included in the BIS stuff, that any realistic treatment of modern combat has to include some addons that provide the missing pieces. (Ex: SAWs, M240s, Combat Optics, RPKs, radios, USMC vehicles, etc....)
I can honestly say that without the many quality addons for OFP, I would have zippo interest in OFP. The Marine Assault Pack units & weapons, BAS helos, Tales of War's AAV, Laser and ORC Russian units, Vit's APC pack, all these make the game playable for me.
And while I agree with General Barron that most people download a new addon, drop in the editor, say "OOOOO", then never use it again. But I actually enjoy making missions with the good ones. They give OFP a more realistic and contemporary feeling that makes it enjoyable for me.
So I would definitely encourage mission makers to use addons, but use them smartly. If I ever do download some else's mission, the first thing I would look for is which addons it uses. If its just plain BIS stuff, I'll pass.
Not that its a bad mission because of that, but I can't get past the really bad models to enjoy a mission using those. As I posted on another forum, no US soldier/Marine has worn a bedroll on his shoulders since the War of 1812
what in the world were they thinking?