When rift released it was such a genuinely fun gamemode that I’m sure a large majority of the community enjoyed to play. It feels like the lack of fun crucible party like modes now is making feel crucible feel stale and samey especially with the loss of other game modes to the DCV. Rift just offers so much like hero moments or fun and competitive elements and to see it in destiny 2 would be really interesting especially on maps like endless vale, javelin or even worm haven just to name a few. This would be a great opportunity to make new maps to support the mode or reintroduce classics like frontier which worked quite well in my opinion.
On the other side, skirmish has always been on of my favourite playlists to have fun or improve my skills in back in destiny 1 as it was relatively smaller and less chaotic than the 6v6 clash counterpart. I feel like reintroducing this mode with more maps too could really set a spark in pretty much the entire community. Especially as skilled players and casual alike can enjoy it.