We'd also rather have a situation where the recipes are selling for vendor cost on the Auction House rather than one where only a few people have access to them (and their respective items). We'll see how things go on the PTR. We also wouldn't be opposed to reducing the drop rates over time if that what's best for the health of the game.
I'm ok with the AH price being close to the vendor price, but I'm pretty sure at 50% that's going to happen pretty quickly, because at any substantial price, people will just farm it. I'm pretty sure at MP0 a lot of people could 5 stack and kill Cydaea in what... 3-5 minutes? And then you could even finish off the old Cydaea/Azmodan run (which could be done in like 7 minutes pre-MP, so faster now... though most of that was travel time anyway) for old time's sake.
Also, what you quoted above is exactly what will happen with the new marquis gems, at least for the first month or two, by the way, unless their drop rate is substantially different than other jewelry patterns.