I am going to focus purely on the aoe aspect of mm for DF and the niche that it has filled for SL as well as having the same design in BFA just with less power. The choice node of heavy ammo vs light ammo is the exact kind of thing I hope we see more of in talent trees for 10.0 and imo is one of the coolest nodes of all those released so far. It allows you to opt into that powerhouse 3-4 target spec that people have come to expect from mm but also gives you a nice option for larger aoe encounters that occasional raid fights/m+ are filled with.
The glaring issue that mm has had over the past 2 expansions however is the way trickshots is activated requiring multi to hit 3+ targets meanwhile bm for example gets beast cleave simply after pressing multi really shows how lacking trickshots is for mm from a QoL standpoint. I believe that pressing multishot should simply auto activate trickshots for TWO targets+ as running heavy ammo for example is extremely painful that you have this beefed up trickshots but can only use it on 2 targets every 45 seconds with volley. I believe that this creates unfun gameplay for mm that could be improved going into DF.