UKC

There aren’t really any proper slabs at the new Big Depot Manchester, roped or bouldering. The closest it gets is barely off vertical for the second half of some of the lead walls. This is a bit disappointing for a punter with no endurance as I am forced to work my weaknesses and can’t hide from my inability to climb any harder than 5+ once things gets overhanging. 
Does anyone know if this is for a particular reason or is it just their preference? 

I would suspect that the wall angles being only a bit off vertical allows the route setters bring the difficulty and angle down with the use of large volumes and holds, but avoids the limitations of easier angled slabs which can become "samey" in indoor setting. 

Plus lower angle slabs take more space and can add risk in a fall (if you can hit holds on the way down). I don't think bouldering slabs are samey.... just the opposite. Route slabs can be, if set for beginner top rope routes.

I recall one of my local walls once set a 7a and a 4a on the same slab line. I considered trying the 7a but decided to pass; I'd be likely to fall off it, with excellent chances of losing a kneecap on one of the huge jugs on the 4a on the way down

I've come to the same decision many times (just never when looking at a 7A ) 

No slabs or real corners/grooves.I think it's all a bit samey tbh

fixed it for you