It is an issue, if you think these guys are better than the reg refs your are wrong and it will be shown the longer they are in.
We all like to blast the regular refs (me included) but they are apt to make less ghastly mistakes. Regardless of quality, nickel and diming officials is a bad thing.
I'm sure there will be growing pains, but give these replacements a few weeks and there will be virtually no difference in performance. The existing refs have been around too long and have become complacent. There should be a maxium of 15 years service with a rotation pools of refs to ensure the quality remains high.