Excuse me I do not understand.. How or in what maner that is giving power to central authorities ??
Maybe that the non popularity and low mining difficulty could open a way to some parties to put influence on it, but what is the correlation between bthe blocks size and this ?
Spamming network could be stoped by simple parades like for example deciding a reasonable minimum fees price ..
Historically the miners have chosen not adopting the block size increase (which in implementation figuring on the original code of Bitcoin) just to assure themselves a good revenue from fees! Even Gavin Andresen was very partisan to the block size augmentation and just gave up from BTC after that episode!
When developers increase the block size, the node software's storage/bandwidth requirements will increase. People will be forced to have powerful machines (PCs) running Bitcoin Core in order to keep up with the huge block size. This will make the network more centralized, because only a small few (mainly wealthy individuals and/or corporations) will be able to afford running a high-powered node. Data centers will be the ones with the most advantage on the Blockchain, leaving the "little guy" (average person) out of the system.
Really? I mean nowadays, when you can easily get micro SDs of 1To and 100Mbts line connexion ??