I guess it's not that simple. That said, it's not that confusing an army. It just has some different things in it. I'll admit I was daunted the first time I read over the list, but honestly, it's no more daunting than moving from, say, Space Marines to Daemons. Sure there are a few different types of units, and the composition can change, but as I said, it doesn't make it any more or less confusing than other armies.Not sure I agree with that.
The Renegades list in IA:13 is very, very complicated. Lots of different options, not just for army composition (it can change depending on the general) but within a given unit as well.
The biggest risk here of course, is that then leaves it open to cheating/abuse, plus most opponent's won't have the foggiest what's what, especially as so much of it relies on conversion work, making WYSIWYG a potential nightmare.
I don't think I'd have any issue with someone using a unit from IA, but a full army? Perhaps not so much.
As to allies. The answer is no. In tournaments it should always be 'no'. Armies are created with built in strengths and weakness. Allies is a cheap way to mitigate any of an army's weaknesses. Also in such a small points limit, it's going to be hard to fit a CAD and allied detachment in the same army.
Also, a basic rule that I and my gaming book stick to is: if you're going to take it, bring a hard copy or a legit digital copy. Torrented copies are OK for general fluff and rule reference, but in a competitive setting, it *has* to be legit. Also, printed out copies of any and all FAQs. If they fail to bring them, either send them to the nearest printer, or they're SOL and won't be able to use it.
As long as players are warned of this ahead of time, no one should be surprised. And if they whine about it, when it's their own frakking fault for not bringing something they were told to bring, they're still SOL.
http://www.lounge.belloflostsouls.net/showthread.php?52423-The-Blood-Pact-Chaos-Homebrew-Supplement&p=472214&viewfull=1#post472214
Its legit though, because CAD doesn't really work well for some armies, Orks don't generally work well in a CAD (although at 900, CAD would be better). But I think you mistook the term CAD for the term Detachment as you said they could use the Codex CADs, when you meant Codex Detachments.
you could add some stipulations for anyone who wants to bring Forge World
-Submit the list beforehand
-Bring the Imperial Armour book
-Actually have the Forge World Model
If someone can do two of the three stipulations, chances are its a player that is looking to have a good time
"There's no use permitting some prophet of doom to wipe all your smiles away!"