If you think #bitcoin is centralized in terms of mining now, this is nothing compared to what it can be when you add large blocks.
I'd be interested to see your mining cost model, that allows you to claim that moderately larger block sizes invariably leads to greater centralization.
Who will mine BTU if they refuse to add replay attacks protection,
Why should BU add prevention for transactions to be mined on competing chains? To do so would be to ensure that there could never be a healing of the forks. This is simply bad policy. Hence, no plans to do so.
Besides, clients are easily able to build transactions in a manner that avoids this issue altogether. Protocol changes are not needed.
thus no exchanges will add BTU,
B does not follow A. Exchanges will deal in the majority chain, or be bankrupted by others that do.