but this is the perennial fusion v purism debate revisited. both methods can yield innovation in principle, but in this case being purist about house probably wont.
My view is that people being 'purist' about house aren't actually being purist at all, but are holding up some false image of how they'd like house music to be percieved. At this point in time house music can be anything anyone wants it to be! F' the snobs!
I don't think grime should slow down, theres a kind feeling that cannot be achieved with these beats slower than 138/140, its natural!... but 4x4 kick drums faster than 130-135 start to get abit 'much' (& technoish)
Nothing wrong with multiple tempos being played over a night tho is there? or, god forbid, a set!!!