Grinding can be fun, when the activity is shorter and the loot is plentiful. It is painful when it takes far too long for a meager drop with a massive perk pool. "Close enough" is usually fine for me in those latter cases, I just want a specific perk or two and if a better one comes along later then it's a bonus. Time gating loot or activities, increasing playtime, and being stingy with loot drops is the worst thing they can do to kill motivation to grind. It is a "looter shooter" type of game or even a "MMO-lite" after all, so some grind is reasonable and expected.