The appropriate method of doing any fork, that we seem to have been
following for a long time, is to get consensus here and on IRC and on
github and *then* go pitch to the general public

So your concern is just about the ordering and process of things, and not about the change itself?

I have witnessed many arguments in IRC about block sizes over the years. There was another one just a few weeks ago. Pieter left the channel for his own sanity. IRC is not a good medium for arriving at decisions on things - many people can't afford to sit on IRC all day and conversations can be hard to follow. Additionally, they tend to go circular.

That said, I don't know if you can draw a line between the "ins" and "outs" like that. The general public is watching, commenting and deciding no matter what. Might as well deal with that and debate in a format more accessible to all.
 
If, instead, there had been an intro on the list as "I think we should
do the blocksize increase soon, what do people think?"

There have been many such discussions over time. On bitcointalk. On reddit. On IRC. At developer conferences. Gavin already knew what many of the objections would be, which is why he started answering them.

But alright. Let's say he should have started a thread. Thanks for starting it for him.

Now, can we get this specific list of things we should do before we're prepared?
 
A specific credible alternative to what? Committing to blocksize
increases tomorrow? Yes, doing more research into this and developing
software around supporting larger block sizes so people feel comfortable
doing it in six months.

Do you have a specific research suggestion? Gavin has run simulations across the internet with modified full nodes that use 20mb blocks, using real data from the block chain. They seem to suggest it works OK.

What software do you have in mind?