The blocksize is meant to increase way ahead of demand. Not in panic "when it is needed", but as soon as possible. Satoshi eventually chose to introduce it as a limit against temporary attacks, not for it to be used as a centrally planned quota.

The OP codes there is still some debate in the community about, but most are onboard with re-introducing many (not all) of them. There have been tests run, as there are quite a few knowledgeable developers in the community. (See Bitcoin Unlimited and Bitcoin ABC teams, as well as independent researchers)

I've not seen Gavin Andresen criticize the re-introduction of the specific OP-codes, at least so far. Even if he does, he is not the sole developer. But a lot of people obviously respect his opinion.