The other major downside of loser pays is that it makes litigation very difficult to stop once it starts - and lawyers, funnily enough, will always say that you have an excellent case encouraging people to start litigation....
A good lawyer will not take a case that you are very likely to lose, and he will advise you that you have no case. I believe a judge can also admonish or censure a lawyer who brings a frivilous claim into court? Not sure how often that happens.
last case I heard numbers on the lawers fees were $500000. This for a case where it was clear they would lose (3 different parties were sued and the nobody could figure out how to split the $100000 loss- that is one party spent 5x the total judgement)