I don't think it'll be bad for FTBers at all. We needed to be prevented from borrowing 5 or more times our salary without having saved up a deposit, as the temptation is to think that if the bank will lend it to you, it will be OK. People have got used to the idea that they can have whatever they want and pay some time in the future when everything will probably work out - not very healthy imo. It's the very fact that those getting their first house now will only be able to borrow a sensible amount - and have saved a deposit - that means prices can do nothing but drop.
I doubt there will be a rush to buy as soon as prices drop 10%, if the trend is still downwards - why wouldn't you wait a few more months and pay less, unless you're desperate to have it right now? Nobody's ever really forced to buy a house, only to sell one.