if they built up to immortals items, they would be used too much. they are already the best items for their gold prices. And it is like that because they dont build up into new items. If they did, I would have to nerf the items.
Shroud still needs a use too though... So, maybe... We can add a few more immortals. but Im not sure if people will get that many. As far as testing is concerned, usually by the time we get strong enough to fight rag; the kill limit is hit. ... like the game used to be played.