Easy fix. Quick play list gets simple mods like old vanguard strike list with matchmaking so you can play fast and feel powerful. Especially during the disposable gear portion of the leveling process. T3 minimum drop & chance to get t4/t5. consecutive play increase chance. gear gives +2 light. You can still use the portal system to assure t4 and t5 gear when capable and adjust how you like as well as the regular matchmaking as is present on featured missions. This allows you to grind enough to easily get good gear in portal custom games but casuals playing quick play still have a chance as well as low light people having a chance at getting a quality piece of loot to make their grind easier. Prime only light advancement only the last 10 light levels not the last 50 or at worst last 2 light. With this setup people always have a chance of feeling rewarded, there's benefits for long consecutive playtime with matchmaking and not solo playing exclusively. And not forcing mandatory power deltas makes earning light levels still feel worth it instead of questioning why you're bothering to level up if you're always going to be at a negative no matter what.