Yes so Black Legion wise (which uses them the most) they have
0-1 SC - Fair enough, like everyone
0-1 Spaceship - like everyone
0-1 Demon Prince per faction - fair enough it makes sense
0-1 Forlorn Hope - I can see this as a proportion of available marines and because scouts with marine stats are nasty, not to mention the fact they can get demons and be used for drop bombardment! But, would the same restriction be achieved to their numbers if they were 25 points higher?
0-1 Raptor - Apparently this is due to background? Though again its skewed somewhat with regards to their power vs bikes. Personally I'd prefer better stating and pointing to make it a straight choice like in the marine list.
0-2 Chosen - Why? Are they rarer than Terminators? If its a power thing would it be solved by making the formations base 6 strong (so cost more) or upping the cost of each unit by 5 or 10 points?
0-2 Assault - Slapped on at the last minute for obvious rasons. The proposal of sticking them in with navy and titans seems to solve it better, though unit balance may have to be looked at.
I don't mind limits for background, feel and rules. But for balance they should be a last resort.
And also of course there is a bit of conciet in there as I feel limits should be built into an army list so they are less obvious (like a core/support split, relative percentage restrictions like 1/3, 1 per x points in the army list and so on).
Edit - this post was done over two days the computer was left on, so the debate seems to have addressed some of this already

Also it more about BL, not iron warriors, here the same restrictions could make far more sense.
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