For what purpose is the bigger block? Why is there a need for a 1 megabyte block, the blockchain works fine like now?
Blocks only get big when there are many transaction in them, so how could a miner create a bigger block without that much transactions
Increasing the limit won't create bigger blocks on average, but allow for it to happen if it is needed. If we stay at 3-4 tps average the change will have no effect outside of occasionally allowing a 2MB block through because of a large fundraiser through lighthouse or a temporary spike in transactions.
There will likely be a middle ground found because most of the other core developers are wary of 20MB being needed. Perhaps if we give some other projects a bit of time to be released like the lightning network we won't need a 20MB limit.