It got removed because Avengers Initiative wasn't selling.

The whole reason why Marvel XP was created was to make a shared universe between games (similar to the Marvel cinematic universe). There was only 2 games connected to Marvel XP. That was a major flaw because if one of their games did poorly, the whole system of Marvel XP gets destroyed.

With the poor sales of Marvel Initiative, they stopped putting updates into the game. That meant that the "shared" universe of Marvel XP is now just only MAA.

After over a year of not doing dossiers, they finally decided to end Marvel XP.

Ne, ne, what level were you in Marvel XP? I only got until Lv7!

Thank you IronspeedKnight, I had no idea

Sadly, if they just maintained it in an "alive" status, they could have added MAAT to it and had 3 games all linked up.

I think it also had very low usage among the communities of either game. I was bummed that I got bored of MAI before getting past level 9. Also, I had friends who got the techno organic endoskeleton as the L6 reward, while I got the Exsanguinator. TOE was the L10 reward once they standardized it. But, aside from checking my progress against rewards, I never looked at XP.

Marvel XP,

Thank you for the free (and then unavailable) Mockingbird.  RIP.