Here is what they have to do:
MAKE BGS FACTION-NEUTRAL (ie, A vs A and H vs H are possible - heck, maybe even teams can consist of a mix of A and H)
I don't know how many times this should be said - faction-specific BGs are nothing but a relic that hurts BGs and does nothing else. Rated BGs and arenas are faction-neutral, because THAT WORKS.
And if BGs are faction-neutral, both blacklist and CTA can be left alone. (See? That's just one issue that faction-neutral BGs turn into a non-issue. There are many others.)