What is wrong with the goal of decentralizing development across multiple competing implementations?

Nothing, but that is absolutely not what is happening. I know this is your new talking point (a very tired strawman btw) Peter but it doesn't reflect on the situation at hand:
A totalitarian power grab for the governance of Bitcoin. Not the proposition of a new implementation but an attempt a hijacking the consensus code behind political motives
Please don't turn into Stolfi you are a valuable asset to this community when your head is in the right place
#1. I disagree. What I see is demand building for bigger blocks, Gavin and Mike providing a solution, and people moving towards that solution. This is the free market at work. If we had several more competing implementations this "consensus process" would be more efficient.
#2. The only talking point the small block side has left is "big blocks = centralization" (which I disagree with but can't prove it). What I find ironic is that they simultaneously fight hard to keep centralization in the most heavily centralized aspect of Bitcoin: development!
If we need centralized development to keep Bitcoin decentralized then we've already lost.
Let's increase the block size
and decrease centralization by showing our support for a wider variety of Bitcoin implementations!