Vote is not good, should strive to reach 100% consensus, and that can be done step by step
You never vote for the answer of 1+1, it will always be 2 no matter what you vote. You don't need vote if a fact is understandable for everyone. The reason why people need a vote is typically because no one can clearly understand what is the consequence of certain decision
I think currently almost everyone have a consensus that block size limit will be raised
First and most important, Satoshi set this limit temporarily, he also suggested the way to raise the block size limit when the time comes. As the creator of bitcoin, his opinion should be highly respected
And from end user point of view, if the system is not able to handle enough amount of transactions, then the payment network will only be able to handle large transactions (Who can afford a very high fee), all the small transactions will be dropped, people have to rely on off-chain solutions which lacks many of bitcoin transaction's superior property, this is not a simple and robust enough solution
So the only difference is that how large the new limit should be, or how fast it should be raised. I think it is easy to reach a consensus of conservative approach when facing uncertainty (If you did not change too dramatically from the current status, you will be very likely to handle the incident if there is any)
A rule of thumb when it comes to IT infrastructure upgrade, you always start to plan an upgrade when 3/4 of the capacity is reaching, and the load should drop below 25% of the capacity of the new infrastructure, means a 3x increase in capacity when upgrading
A 100% consesus is idealistic bullshit.. You will never get everybody to agree on some solution, that is just not how humans work. There are always some ego trippers that want their solution and only theirs..
The 90% that is being proposed is already quite high. 60-75% would be more realistic imo.