yes the voting has issues.
The biggest issue is the role the block size cap should have in the network.
Satoshi, Gavin, et al. see it as a "sanity check". In software this is essentially an exceptional condition -- a value that the system should *never* exceed. In this perspective, miners can individually produce smaller blocks (regardless of pending txn count) so why create a mechanism that essentially forces a cartel (collective behavior)? The only reason would be to maximize miner profitability by manipulating the supply curve. Closely tracking evolving network and disk capacity is not necessary for a "sanity check" because most miners will simply start mining smaller blocks (than the limit) if network and disk stop following moore's law.
Others want the max block size to be an entity that can be used to actively manage the network. Presumably if miners are noticing a lot of "spam", but a "misbehaving" miner is mining it, they could vote to reduce block capacity to eliminate this spam. Also, voting lets the limit more closely track the evolution of network and disk capacity.
Let's assume a spam attacking misbehaving miner ala the large miner, large block attack against small miners that was initially a huge FUD advanced by Wiulle and others that you don't hear anything about anymore. Simple defense, just mine a 0 TX header only block during the time of your large block processing. This is the practical defense that Wang Chun told us they do and that we've witnessed they do during stress tests. And this defense can be done irrespective of whether as a miner you are connected to Corallo's relay network or not which those Fudsters love to go on about.
Point being miners can and should be encouraged to track TX's and fees and construct blocks appropriately based on their own internal metrics and profitability. Core devs can't possibly do this.
Yes, you could accuse Gavin of trying to be a one man predictor for network growth at this point but his proposal is based on sound growth projections with the larger point being that he is trying to automate out as much human intervention, voting manipulation and need for future forks as much as possible.