I like Mousasi a lot, and think he's one of the most underrated fighters here in the USA, however;
1) He needs to start fighting higher ranked opponents, not only to challenge himself more (you improve by fighting the best, particularly when you are one of the best), and to improve his credibility and marketability.
2) Come back the USA, and begin training heavily with a wrestling camp, or hire a bigtime collegiate wrestling coach. His game is one of the more complete games in MMA, but his lack of TDD and general willingness to be on his back (like Donald Cerrone), will continue to be his downfall in any USA MMA organization as takedowns and top control get too highly scored for his style of fighting to win in a decision fight.
Side Note: Does anyone else feel every time they watch DREAM that they're reminded why MMA should be fought in a cage NOT in a ring? All the restarts I see in all the ring based MMA promotions and the tiny little asians pushing guys hastily back into the ring, I cant help but think "why the f*<k havent you guys switched to a cage yet?"
Again I like Mousasi a lot, one of my favorite fighters actually, but he's got some priorities he needs to change if he ever wants to be a top 3 LHW again.