Wouldn't it just be better to add replayability through other content than through grinding? Personally I would prefer more activities with random modifiers. Have the 3 story missions you can do weekly have random modifiers. Make public events with random modifiers, or something similar to Court of Oryx or Archons Forge, while this would be rehashing old content it would add variety to what we have. While grinding is a necessary part of this game, it shouldn't be the only the thing to do at end game. I would prefer something with more substance than chasing a carrot on a stick.

"The Science Behind RNG: it's gambling RNG and luck in games is essentially gambling, and it is very addictive. For every low there is a high, a big epic moment, and that is what players want. From getting that impossible winning draw to getting a perfect run, players keep playing in order to get that rush. The thought of getting that rush, that one win, is what keeps people playing and it's what causes gambling addictions. Gambling is very similar to addictive drugs when it comes to what it does to our brains. A human has a reward system in their brain that releases a chemical called dopamine. source: https://www.gameskinny.com/pvp33/why-do-gamers-like-rng-based-games

I get what your saying but random weapon rolls are not what made Destiny so a great game, lets be honest. People are blowing this way out of proportion. Sure, I see the value of RNG weapon rolls giving some incentive to grind for a weapon, but I also can see the issue in PvP where a lucky roll results in unbalanced matches. I personally have been a fan of a separate weapons balance for PvE and PvP but I get the issues on why that isn't really plausible. D2 has a lot of replayability, but it might not be the style you're looking to replay. For instance, each planet has it's own planet specific loot, do you have all sets of armor? Do you have all weapons max light level, all the exotics? Do you have a warlock, hunter, titan all 305? I get some of that stuff is not too important to you but it exists as reasons one may continue to play. I do agree some shortfalls of endgame are present. They need to add more milestones per week. Flashpoint is a breeze, especially with other people doing public events. The clan XP gains just happen whil you're doing everything else, and crucible is over in 5-6 matches (which is fine for me because I never liked the PvP in Destiny). Why not a milestone for % like flashpoint but for a strike playlist? Why not milestones for completing X amount of lost sectors on X planet? Cayde-6 Treasure chests have options for exotics and other stuff, but why not a treasure map with clues you have to solve (steps) that ultimately leads to a hard to find/obtain chest with power gear? So many more ways to add replayability for milestones, but now you're limited. I don't get to play much being 32 with a family and career, but I finish all the milestones for my hunter Tuesday evening with the exception of nightfall and raid (I save the nightfall for my clan Sunday morning and Raid Thursday nights). More milestones would be great. I do got to say I like the faction rallies. Altering lost sectors and get faction specific gear is a cool idea. I just hope they add some new stuff next month like they promised.