There's nothing inherently wrong with a crossbreed per se, but there are a lot of potential problems with the majority of crossbreeds which people are buying at the moment
Most, not all, but most are being bred for money - and people are charging more than the going rate for most pedigree breeds at the moment
Very few have had appropriate health tests for both parents
You could get the best of both breeds but equally you could get the worst - there can be such variation in a single litter with first generation crosses that you really don't know what you're going to be getting
Maybe eventually if thoughtful breeders get involved mating a really good example of one breed to a really good example of the other then in time there might be standardised cocker/poodle crosses, but that's not what's happening at the moment
Some of the big kennels are doing it on an industrial scale, churning out hundreds of puppies - already these are getting rid of their standard poodle studs and bitches as labradoodles are no longer as fashionable as cockerpoos, maltipoos, cavachons etc etc are currently more popular