The quote in the first post of this thread is a good hint about my feelings on half-priced nobles, but just to be 100% clear: half-priced nobles are a terrible idea.
There's a lot of discussion above about the influence it will have on game mechanics and how that affects the world, but my objections are rather more fundamental...matters of principle, really:
1) Changing the rules mid-game hurts gameplay
You're playing a chess match, and at move 20 your rook can suddenly go diagonal as well. You're playing tennis, and after the first set it's announced that a set will now consist of 3 games. You're watching a football match, and at halftime the referees decide that a touchdown is now worth 12 points.
Does this help the game? Make it more fair? More interesting to play or watch?
Half-priced nobles are no different from the examples above. We started the game under a specific set of rules, we obviously liked those rules since we're still playing, and changing the rules mid-game is a ridiculous risk to take.
2) It sets a dangerous precedent
Half-priced nobles seems like a big change, but it also means that the door is open for more changes. Why not give HC twice their attack and defense ratings? Or let scouts lower loyalty by 5 points? Make nobles move 3 times as fast?
These examples may sound extreme, but half-priced nobles is also an extreme change and there's no guarantee that that'll be the only change. Once we start tinkering with game mechanics, all bets are off.
3) It dumbs down the game
W16 has 309,955 villages, which means that over 300,000 players started or restarted on this world. Out of that massive amount, only 1000 of us are left. We've all proven that we could survive and prosper while 99.7% of the competition is already dead...quite an achievement, and something we should all be proud of.
Do we really want to ruin that sense of pride and achievement by making the game easier? I'm strongly against dumbing the game down...I like that it's difficult, since it gives me a better feeling if I succeed.
Bottom line: a vote for half-priced nobles is a vote for more randomness, less fair gameplay, and dumbing the game down. The only people who would vote for that are the people who lack a spine and can't cut it under normal circumstances, and they should be deeply ashamed of themselves.