How would changes to the Bitcoin protocol be decided upon? What constitutes a "majority"?
"...if it benefits a large majority of participants.", nobody proposes anything ever that will not, at least be presented as, 'benefiting a large majority of participants'.  From 'trickle down economics' to 'you might not agree now with me on this proposal, but you'll agree with me later' gives the people that set the agenda and write, defend and prepare these proposals and technical changes a lot of influence.

secondly, normal politics (as this is politics, not engineering primarily, as for instance now BIP16 and BIP17 are evaluated for implementation and the developers do not agree and seem to have valid points.) 

Although i don't get the impression that the bitcoin developers have dark motives, or don't want the best, i am worried about what is going to happen when the US government starts to try to exert influence over bitcoin. There are already BIP proposals that for instance make it possible for someone to request a payment from a customer, and this greatly reduces anonymity but increases tracability vs. for instance the implementation of zerocoins which would build in automatic mixing and increase anonimity. the US govt, or any government for that matter will use their influence and also power to try to safeguard its (perceived) interests. (i don't know which BIP's these are - but you get the picture)

Actually, if i am not mistaken there is no bitcoin protocol as such, there is just the bitcoin-qt client, a piece of C++ code that is hard to understand (unless you're a C++ programmer) and by the sound of it not unambiguous. This is the protocol, the protocol is written according to how this program works. 

Anybody has any illuminating thoughts or facts on this issue?