Have to admit it goes from one extreme to the other. You do a mission on your own and it takes hours like you say hiding and taking them out one at a time. Then someone joins you and you blast through it in 15 minutes...
Yup its designed to play in a team you know well, i can understand why they say raids are only available for friends. We tried the weekly level 22 heroic strike Friday. We were 22 and got annihilated by the first mob. Accept defeat and had to go level gear. Went back last night and dam me it was still hard. Still, took down the first mobs then in the second room got annihilated. Ok some serious tactics to change, try again....nope that didnt work....try again ooooo yes we goth through. What a great feeling of achievement. Next room annihilated.
The game is repetitive and at present fairly limited, gear drops are random and you have to grind rep (mmo rpg anyone) and the story is very weak. But when you play with friends you write your own story, you dont mind the repetition as you chat away and divert off story to explore and the sense of achievement is great when things click and you beat an impossible task....but then you move on to the next one.
Agree its not perfect but so far its a hell of a lot of fun, but if i was playing solo i think i would already be back on forza