don’t get me wrong, great DJs are a joy to watch - Youngsta at the moment is on fire in dubstep - i just found it refreshing that grime came with a different emphasis. It's more punk - slam a tune on - it's all about impact not soporific seamlessness. and anyway half of the momentum in grime comes from the MC (why else would devil mixes have worked?) which is far more flexible a medium than beats on a 10" press.
another negative 90s dance music point is that DJs and DJing has a constrictive effect on arrangement. All tracks must be fixed tempo, have a sparse drum intro etc etc. Grime, which evolved mostly on pirate radio ie free from the constrictions of making people dance, brought new structures, or at least ones with a nod from dancehall and hip hop (not forgetting the influence of Fruity Loops, which forced early producers to use 'switches' ie 8 bars not elongated arrangements).
as an aside, just as grime threw out mixing, it also threw out the emphasis on drum programming. Target beats are like awesome exercises in r&b-informed condensed minimalism. the perfect 3rd-beat skank, with nothing else required - they're a joy to listen to. this approach allows space for sonic experimentation it seems. ( and this approach has also informed dubstep over the last two years too, with half-step etc.)