You can't really grind for a particular weapon. The loot is controlled every week, every month, every 3 month... some stuff you can't even get now but other people have it.
Its really not solo-friendly. If you want top-tier weapons, you need a strong team.
PVP is a fast movement with high time to kill which I didn't like. It's 3 shots with a handgun to kill someone. Think about think, it's not that fast lol. So it favors team-play a lot. Plus everyone has a high health regeneration.
Long rotating timeline for some activities and some weapons (months). Weekly challenges that encourage you to play stuff that otherwise you would not play. Overpowered abilities in PVP that you can pay for. Extremely low drop rates for the loot pool that is not exclusive thus always accessible. Almost impossible to feel accomplished as a player.
I thought that Runescape had some low drop rates but Destiny does worst.
Just a horribly designed game hidden behind lore and good visuals!