You hit the nail on the head with the "convey" question. A fairly large number of people think there's a good chance that the AGPL is redundant because the GPLv3 is broad enough in its range of likely court interpretations. I've flip flopped back and forth on the BSD/GPL side of the fence a number of times, lately I've started moving back to BSD-land again. (Especially with things like the "Do what the fuck you want" license, version 3.)
I don't buy that. I find it hard to believe that a court could find that a slightly ambiguous clause means something so different from what the people publishing their code under it understand it to mean. If AGPL didn't exist, and if everyone using GPL claimed "convey" included a hosted service, then there'd be a case. But given that AGPL exists, and given that the intent of most people who use this license is not to prohibit hosted services, that's a major stretch.
Interpretation of contracts is not necessarily based on intent, especially if you're using someone else's contract, and especially if it's not a consumer contract (where, in many cases, a contract deemed to be deliberately misleading may not be valid).
