1. The new weapon system. All it needs is better diversity, and perhaps more weapons like Fighting Lion, which is an exotic Grenade Launcher that can be used in the Energy slot instead of the Heavy slot. It would be nice to see other exotics that are "out of slot" for their type, allowing more build diversity. 2. 4v4 PvP. Some people are going to like this format better, some are going to prefer 6v6. This is an opinion, not a problem. Personally, I can't imagine putting 12 people into the current PvP maps; it would be utter madness! 3. PvP time-to-kill. I'm struggling to understand why anyone would want the D1 time-to-kill back. The longer D2 TTK results in more engaging firefights, the ability to make feints and flanks, and generally more exciting PvP. Regardless, this is again an opinion, not a problem. 4. Nightfall Timers. It's there to keep you from creeping through a Nightfall, playing extremely safe, and thereby trivializing the challenge. As an endgame activity, Nightfall Strikes are supposed to be challenging, and the timer is part of that challenge. There are a lot of issues that need to be addressed -- many of which have been recently acknowledged. The game is indeed far from perfect. But these four specific design decisions aren't likely to change and arguably shouldn't.