played him once and played against him once, havent seen him with a mom + maelstrom, but it sounds sorta ok with the short duration and mad range on his % thing.
doesnt seem necessary though, the % burn doesnt stack and there is enough time to get it spread out on the team.

seems like he can do ok as an offlaner if you can get some early levels, good nuke, good heal and crazy range with good counter engagement from the ult.
his escape is pretty useless though in the offlane, not many places to use the flying thing.

he looks pretty flexible and the dotabuff hero healing stats you get from him are crazy.