This is currently addressed by : Retirement, when it makes it's triumphant return. You should now be able to do it for free (and even gain an heirloom for your next build).
Also, chadz has made the suggestion of allowing a character start at level 25. This character wouldn't gain any xp, it would be forever lvl 25, without the ability to retire. This would give the benefit of being able to have a usable character right off the bat, so that you could try any play style you liked.
I like the retirement concept only problem with it. It takes for ages if you want to try and play different roles. And then there are mistakes made sometimes and you can only do it right when you start from scratch. If you want to try out different roles which perhaps are more fitting to your playstyle you need a new character.
I wouldn't want that retirement is gone for good, the heirloomed items and the better xp/gold rate you get afterwards are insentives enough in my opinion. Instead let be more flexibility.
The only counter argument i could think of are that players would say, mmm now he has gold and stuff already and didn't even need to learn and earn it with a new character the hard way. But when you played a character long enough, sometimes you wanted to just try something different, you for example picked up in the forum. And when you then see, it is not what you wanted you have to wait a week(at least that was before the patch). And when a player plays a long time(not speaking about me yet), he should have picked up some skills of his own which can be aswell usefull on a completly different character.
I would still retire but not because of i want to change my playstyle or stats but because of other nice insentives like heirloomed items and more points to spent on weapon proficencies. That would also be the reason for me not to go for a 25 fixed char, because it is not the best i could play for. And
why should i miss out of being a peasent again , thats fun too and remmebers you of where you come from and that there are allways folks out there who are new and need protection. It is allways a heroic victory for a peasent if heeven was engaded into battle to stay at least alife till end of the round.
Problems as i mentioned would be there, if you had the existing characters merged. That i can imagine would need some havy duty on the database and perhaps even some balancing because of the gold piles streaming into one account.