Re: Avengers 2 and X-Men DoFP are both using Quicksilver and Scarlet Witch
They are equal parts Avengers and X-Men material. Thus the legal disputes. Especially in the Ultimate universe which has been the most prominent in the last 10 years.
Nevertheless, I am okay with their addition so long as they have absolutely nothing to do with mutant-kind (which is lucky because they aren't allowed to).
On the other hand, if they imply Pietro and Wanda are mutants without actually saying it I will be pissed because there has been no mention of Wolverine, Magneto, Xavier or any of the other FAR more important mutants of the Marvel universe.
And on the other, other hand, if they introduce them without any explanation of their powers I will be just as pissed because that's not what the MCU is.
I like the terigenesis/Inhumans idea, or just about anything having to do with the High Evolutionary. I'm actually rather against the Extremis/brain slot idea at this point. As it's terribly boring.