I see, there are people saying that increasing block size will increase centralization. This is true. But, the heart of bitcoin, i.e. mining, is already centralized. And this is due to pool mining. I hear, miners will decide with their hash power that which BIP will win. But, this is practically pool owners are chosing, not an average miner. If you want to stop this centralization, break the pools. This requires capping the difficulty, not the blocksize.
mining pools do not "centralize" bitcoin.
for example, the current voting going on isn't made by the pools individual miners of that pools choose what they are voting for.
and if a pool ever do not operate to an individual's liking he is free to choose a pool that dose.
if anything pools allow for further decentralization of bitcoin mining by allowing small miners to continue to mine at such a high difficulty.