UK has been trying it's very best to ensure EU stays as decentralized as possible. Look at it from a bit wider perspective, keeping organization decentralized and decentralizing it aren't fundamentally different actions.
McHrozni
I would disagree that decentralisation results in a weaker union. (Of course this may be true for the UK in that decentralisation by having devolved parliaments does seem to have resulted in potentially destroying the union.)
The US has a very decentralised federation, e.g. small towns will have their own police. Yet one would not say that the USA was a loose and weak union. Germany has a strong federal system that decentralises power yet it is not a loose and weak union.
Question 1) How has the UK kept the EU decentralised? This would need to be a case where solely the UK was responsible.
Question 2) How does decentralisation weaken a union?
In principle I think that subsidiarity / decentralisation is a good thing. I am for the EU, but not as a unitary nation state where all decisions are made in Strasbourg / Brussels.