I don't know if this has changed with 2.4.1, or if it's some different graphics settings on my part, but lately I pretty much can't see a player that has invisibility, even if I'm right in front of them. There's still something, but if I don't see them shooting, I'll likely miss them.
I don't think that is all that great. Especially on instagib where 30 sec. of invisibility can give a serious frag boost.
- This might be a thing for the mappers but I also think the 3 extra lives you get with extra health is also too much of an edge for just picking up one item.