Destiny is a wonderful yet fairly flawed game. People have been vocal about real problems and trivial matters. Let's look at what's worked and what hasn't.
So to scratch one problem off the list loot isn't really broken. It's just not really well implemented. Drops are random, they're designed like any other game with random drops to slow down player progress. That's why destiny also has marks, a currency that accumulates over time to be spent on legendary weapons. If you have been playing the game since launch there's no reason not to be fully decked out in endgame gear after 2 to 3 weeks.
However, buying gear doesn't really feel great, does it? Yet Destiny's other option for getting strong gear is the Exotic bounty system. Basically people are given bounties that have fairly absurd demands to complete for a guaranteed top-of-the-line weapon. Then once said weapon is in your inventory it's now your job to try and level the weapon up to the point that it's not one of the least effective weapons in your inventory.
Where the upgrade system for weapons feels fun for the early part of the game it quickly becomes a grind on the later weapons. A bird in the hand as they say.
So there are a number of solutions for the weapon problem right now. One might be creating a tougher strikes playlist that eventually gets really difficult but will guarantee an upgrade to a player upon completion-like your pants that give a boost to pulse rifles and are rare might become legendaries with an upgrade to primary weapons or that legendary hand cannon might become an exotic or just upgrade without costing you any materials. They'd need to keep elements random since the gear up to endgame really isn't supposed to be too quick, but having a fun activity that has a great chance to improving your gear would possibly pull people away from shooting at that damn cave.
The next big problem is that destiny's non PvP game feels a bit off. There's the game's "story" content that is pretty enjoyable while you're lower level and then a huge blank spot until raiding. The game doesn't really have anything of a midgame. From people's descriptions of the raid there are unique elements that make the encounters interesting-this is something the rest of the content doesn't prepare you for at all.
If Destiny's preferred endgame activity is raiding then it needs those dungeon level events to let players learn what to expect and better ways to work together. For most of the strikes, if not all, there doesn't seem to be much incentive to work together as a group beyond clearing the event faster. Basically Destiny needs content that uses the class mechanics and the environment in interesting ways yet doesn't demand weeks to gear up for.
Honestly I can't really offer any real advice, this is just straight up content that should have come with the game. I tried playing a strike on the level 28 difficulty and it was a joke. The problem is you won't really get any more rewards for the effort and the only real change is the tenacity of enemy shields. This doesn't really have any room for tactical development of players: you literally need strong gear to clear this stuff since it's still exactly the same as what you've dealt with before.
One idea might be allowing people to adjust some of the modifiers for strikes so that you could do the content at a level you can handle with a bit more to think about along the way. Another option is to let players wager before strikes on a series of challenges to take on for some sort of benefit: maybe not dying once or not letting anyone in your crew respawn. Or, you know, they could release a bunch of free content with this level of difficulty in mind.
Now for the part where I mention some of the things that literally just need to be fixed: proximity chat of some sort, drop in/drop out fireteams so joining with someone obviously going on the same mission doesn't mean I have to jump to orbit, volume controls for sound, and a better emote system. Possibly adding endless bank space for emblems/shaders and control over how this cosmetic stuff actually looks-like applying shaders to everything except your already awesome looking gauntlets. Giving the fireteam leader the ability to highlight an enemy to focus on("wizard on the right" is not helpful) and the ability for re-mapping controls /emotes. During a strike I'd love to be able to just push a button and let players know adds have arrived or that I found a chest so being able to have defined chat options might be nice for people without headsets. (Also it means I can listen to my Best of Curtis Mayfield without driving other players in a fireteam nuts.)
Destiny is an interesting game that desperately wants to create a community. However it seems like they haven't really made those tools yet. The Crucible PvP is one way you see this in action. Every weekend they have new modes available to play and daily bounties to work on that mean players who might generally prefer more traditional shooter tactics will be going for rocket launcher kills or shotgun kills. Seriously it's some of the best multiplayer I've enjoyed in years, but it has weird problems. The game has 10 different maps but without any sort of voting system the game constantly throws the same 3 maps up. I literally haven't played on all 10 maps yet. What the fucking fuck?
The multiplayer could really benefit from a few more constant modes added to the options and maybe an option to go into an open chat lobby or not. I do enjoy playing a game in peace and quiet, but I would love to coordinate with players doing objective based modes as well. As well the game should have some sort of "hardcore" options available as well to allow players to really test how well they know the map and their skills.
However in many ways the PvP in Destiny appears to be the most polished section of the game. From the way that daily bounties affect gameplay to the way new modes are dropped in over time it's the most accessible aspect of the game. Over time what I think people really want to see is this quality in the rest of the game. PvE content could be a lot more interesting across the board and should be focused on allowing players to advance a more tactical and team based combat approach. The shooting is fun but the game isn't very good about getting players to think-and that's because the majority of the game doesn't demand or reward this.
In the crucible you have to stay very sharp since every player has access to instant-kill abilities. This creates a heavy challenge to overcome each match and a unique set of risk/reward problems arise constantly. However the rest of the game doesn't seem to cater as well to this player demand. The "harder" options for most of the content are just raising shield resistance strength on enemies and the like-which wear on the player over time as the more uninspired sections of the game don't have any real options besides dropping loads of bullets into enemies.
If Destiny can work towards adding more challenging content that doesn't require a heavy gear check then it really does have a long life-span. The game has fairly solid mechanics that, if properly tweaked, could really create a game deserving of the communities' support. Honestly though I think a lot of people are going to be dropping Destiny in the coming months and without some continued support I don't know if the announced expansions will be able to stand out against new games this fall.
Nevertheless the word is out on Destiny, it's problems and all, so the ball really isn't in gamers' hands any longer. Let's see how and when Bungie/Activision respond to the criticisms cause either this game truly will crash and burn or we'll see them right their course. However after getting a taste I really wonder if gamers will be as accepting of some other releases that don't even attempt to innovate. Honestly a person can say what they want to but at least Bungie really has tried to innovate with Destiny.