I strongly suspect that Adam does not have any intention of implementing that plan, certainly not before the network gets saturated. I believe that he made that proposal only to pretend that he is a reasonable guy, and to steal support from BIP101.
The quality of saturation is the critical element one should be worried about.
Saturation from dust, spam, worthless micro-txs, faucets, dice, "stress tests", scripts that are purposefully wasting space in the blockchain for minimal fees, etc = nobody should even bother.
Saturation from legit txs should get a bump to accommodate for new capacity.
If you enlarge the block size prior to being genuinely saturated, you are just opening the bloat-attack-vector, wide open. And then users will say 'ohhh, this is bullshit, this program BTC requires me to download 2 tb of data prior to using it"... or, if someone is in a country where bandwidth is expensive and they are charged for over-the-top use, after, say, 100gb/month, "aaah, I can't even sync this without going over my monthly quota". Or "shit, I have to send these money out, and I'm syncing the last 30 hours and it takes an hour to do so"... because 8mb blocks are full of cheap spam and dust.
If someone says "but we can send these users to thin clients, web wallets etc", just contemplate that if this happens now, and having your own bitcoin-qt is unsustainable for a lot of people, then what will happen in 5 years or 10 years?
Block size needs a glide path that co-incides with actual usage, and marginalizes spam/dust, or makes it expensive for such txs.