A block size increase “based on demand”, and leaving it to the miners to decide how large the blocks should be “based on demand” is a very dangerous proposition, topcoin360. It will open an attack vector, that would possibly disrupt the network.
If you're worried about a congestion attack with a higher limit
Why would I be worried about network congestion when the miners can increase the block size “based on demand”. What you should be worried about is the centralizing nature of your proposal, and how a cartel of miners can exploit the system by faking demand. Like what gmaxwell mentioned, Calvin Ayre has been faking demand in BSV. Haha.
then you should also be worried about a DDoS attack with a lower limit. Idk what the exact limit should be, but I know that it should be updated more than once every 10 years.
This might be a stupid question, but does small blocks make Bitcoin more vulnerable to DDOS? I thought one of the reasons there was a 1MB cap on the block size was to help prevent DDOS.