Like you, I haven't seen the piece.
It's perfectly possible for a piece of work to be innovative, new, exciting, edgy, dangerous and also appalling, so I think it's unfair to assume that people who think it's rubbish are doing so out of ignorance. The mere fact of being innovative (etc) doesn't guarantee success. One possibility is that the audience isn't up to speed with the innovation (etc) of the work. Another is that it's genuinely dreadful. That the company has a strong track-record is no guarantee: after all, the RSC and the National have done the odd piece of half-decent work in their time, but have also produced some shocking turkeys.
I also think that if a production is produced under the imprimatur of the RSC, it's not unreasonable for people to assume that it is in some sense related to the RSC, and in some sense related to their standards and history.