PAX Weight/Build limit
I agree that it's not pleasant sitting next to overly-large or unpleasantly aromatic folk for any length of time. The weight thing I can accept is sometimes caused by factors outside the person's control but I cannot abide the b*gg*rs who can't be bothered with basic personal hygiene - the latter should not be allowed to board!
It does seem perverse however that despite documented scientific proof that the human race is getting larger (& I don't mean obesity but physiological/genetic generational growth), airlines insist on cramming in more seats & demanding ever smaller a/c. I can siympathise with their need to make money but it's getting beyond a joke. Fortunately I am able to travel busi class on LH but the many European SH's I do are becoming increasingly unpleasant as the result of the attempts at miniaturisation by some carriers. I particularly cannot stand Embraer 145's which, for anyone over 5'6" and/or 11 stone, are a pain in the neck ( and back, ass, legs, shoulders, etc.). Throw in the current inclination for folks to take all their earthly possessions on as hand baggage & the flight becomes a real penance. Mind you the 146 ain't much better.
If the carriers have to increase prices to provide a civilised service then so be it. Sorry to sound harsh but air travel isn't a privilege, no matter how many chavs think it should be!