What can be dangerous is to change from what you are used to.
Personally, I've always had my front brake on the left and rear on the right - I think this is preferable, especially for a right handed person, but any advantage of one side or the other is insignificant compared with your conditioned reflex.
Interesting, I feel the opposite way for the same reason. I prefer to have my dominant hand on the front brake which requires more precision and power.
Well, each to his own, chaqu'un a son gout!
My take is that the back brake needs more pressure because it's less efficient and the longer cable causes more friction.
I agree with Ed.
What can be dangerous is to change from what you are used to.
Personally, I've always had my front brake on the left and rear on the right - I think this is preferable, especially for a right handed person, but any advantage of one side or the other is insignificant compared with your conditioned reflex.