I hear you. Some have said the only way to get the core back is random rolls, weapon slots plus a new raid to drop a the same time.
This raid was fun but I personally think we didn't give it enough time because if I'm honest it was slightly harder than some D1 raids and we gave up too easily as a clan because we started to realise there wasn't much variety to do stuff inbetween raids.
Problem with the lair add ons are that they don't have the rewards to bring you back. Equally there's no mystery to them as we all know they'll be on the big planet eating ship.
They are making changes though, to the point of Nightfalls, as the timer has now gone, replaced with a challenge timer that you can ignore if you want to.
I want a really good Prison of Elders with progression levels and valuable loot to grind it all day long.