The one where we don't fill the chain up with arbitrary data. Where we don't pretend there's no obvious difference between spam and actual transactions.
Discussion
You made a claim about the block size debate. A quite bizarre claim. Nonsense data was a very important part of the block size debate. Why do you say otherwise?
I was always under the assumption that the competition for block space would always be among genuine transactions. Now you have people paying $100 for a $1 transaction (that's really some other bullshit).
Maybe some people were expecting this? I certainly wasn't.