Patrol needs to be updated badly as there is virtually no reason to really do it at all in the game besides bounties. Returning the flashpoint challenge would be nice I think and updating lost sectors to give a reason to do them even when its not the daily exotic lost sector would be nice also.
I don't like timegating in this game but I know its somewhat necessary for the seasonal model, I'd much prefer the seasonal story to be delivered every couple of weeks rather than a crumb of story each week, at the moment its pretty much just log on to do a single battleground and get a 2-3 minute cutscene or have a 2-5 minute small mission.
Seasonal upgrade grid needs to go or we need things similar to Dawn and Worthy where they aren't exactly timegated just grind gated and the upgrades allow for more ways to get the seasonal loot via weapon bounties like Dawn(which gave a reason to do patrol content) which would include reprised older weapons as well. That and using more of the actual game currencies in getting upgrades like Glimmer, Legendary Shards and cores rather than timegating them via seasonal challenges.
Getting above level 100 should grant some level of reward each level even if its just a small amount of glimmer or shards or a enhancement core. Would help newer players that just got into the game get some amount of necessary resources by playing a bit more.
I think if the seasonal activities were more like Dares where there is more randomness to the encounters I think it would be better like if Ketchcrash gave you 1 of the 3 bosses randomly each time at the end rather than a specific one(except Master mode tho).
Weapon crafting needs to be tuned down since its killing the loot side of this game where I don't feel the need to really farm random rolls and instead just farm red borders of drops. I think Raids should keep craftable weapons and maybe dungeons but seasonal weapons shouldn't.