Everyone has their own reason why they want it one way or another.  In China's case they want the blockchain to stay at 1MB due to being behind the Great Firewall as it is called.  The issue with them would be the fact that it would take longer for them to hit a block than it currently does because it would add more data to get through their Firewall.  Although that isn't such a bad thing, it would cause Mining Power to shift a bit and would probably in all honesty make the Mining Powers more diverse than it currently is.

Raising the blockchain limit to 2MB also causes another issue with Hard Drive space.  Some people tend to think that it would create an issue for people running Nodes currently because the blockchain size would increase too much causing people to have to shut down nodes.

Either way you go about it, this whole blocksize debate is somewhat negligible.  Typical growing pains of a technology getting a lot of recognition and adoption.  Same thing happened with the internet when it first started.  There would be times people wanted to get online but couldn't due to network congestion at peak times.  More or less the same thing that is happening to the blockchain.  People want to make a transaction and can't because there are a bunch of other transactions being processed so there is a delay.  Of course now we have the internet as we know it without having to use phone lines etc.  My basic point here is that it will eventually sort itself out in the end just as the internet did, just takes some time to get things sorted out.