Well, Segwit2x could impose a second popular segwit-capable wallet implementation, apart from Core's AXABlockStreamCoin . In any case, Segwit itself is not what leads to a "wallet implementation centralization". This centralization has more to do with the tradition to regard the Core client as the "reference implementation". But Core formally is not different from any other development team that tries to code and distribute a Bitcoin client - only these informal mechanisms give them so much power over code and protocol. As already said, Segwit2x could change that, so you should embrace it if you favour a more diverse "development ecosystem".


With Segwit2x we'll get probably about 4 MB blocks. Isn't that exactly what you want?