In theory it would be a very good thing long term!
The reason we got in this mess is the banks started to lend silly multiples and percentages to people, so the credit was there and houses shifted and kept going up in price. Unfortunately, it all ended in tears when, low and behold, it transpired that lending people 110% mortgages at 5* their salary wasnt actually a great idea because people cant pay them back.
The average salary in the uk is £26,000.
The average house price is £161,000. (6 * salary)
Theres something wrong there (and yes, I realise that averages dont tell the whole story), so assuming that banks go back to the traditional 3.5 times salary, sellers have to take the decision to either stay where they are or drop their prices to within what buyers can afford.
Of course there are a lot of people that would be royally ****** as they would be unable to move house, stuck in negative equity, but at least in the furure average hard working families will be able to afford a house.
Firstly, an individual does not have an entitlement to a house, nor does a couple, but it's certainly reasonable that with a limited supply, those who can provide two incomes are in a better position to purchase than those who only provide one.
Secondly, and related to the first point, most banks did not go that far about the 3.5x, the difference was they started taking into account income, rather than salary, so a household with two incomes could borrow 3 or 3.5x joint, which is essentially the same as the traditional 3.5x income where there was a single earner...
Thirdly, the idea of 5x mortgages simply did not happen in the way you are claiming. The only bank that was routinely offering 5x salary/income was Abbey, and the offer was subject to strict criteria (including a deposit and a household income in excess of £60,000). A couple of other banks offered similar products briefly, but it was not ever routine.
http://www.iii.co.uk/articles/articledisplay.jsp?section=Mortgages&article_id=4836291
The mortgage providers in the UK (with the notable exception of B&B, who lent to the wrong people and bought the wrong mortgages from the US) are not suffering because of repossession or arrears rates on their mortgages, they are suffering because liquidity has dried up due to a lack of confidence in the securities market meaning virtually all mortgage bonds, whether good or bad, are worth very little and unwanted.
Put simply, the reasons you are citing for the cause of the problems have not caused it, and are being seriously overstated in that regard. The UK did not have a problem with excessively risky lending, nor did we mandate subprime lending (as they did in the US) as being compulsory.
Of course, I'm not saying that everything above is a good idea, some of it certainly isn't, and the continued issue of people borrowing more than they can sensibly afford is not going to go away, but it's not the problem at the moment.