I definitely think that music made by people making what they want to make is usually better than those that change for what they think will be more popular however I also want the artists to make music that I like and if they don't I should be free state my opinion be it constructive or not. People don't always have to be constructive when they critise music, sure it is better to be so but if I want to say that such and such is shit because I hate it and it's shit then so be it. The opinion is not invalid because I didn't detail the ways I would make it less shit.
Basically I think artists should make what they want to make but to take any critism (constructive or not) on the chin. If they can't handle critism then they shouldn't release their music. Someone somewhere is always going to hate it and in our annonymous internet world they will have no fear saying it, a lot.
All I hope for is that I can find artists that make music that I really like, from their heart. Generally they'll make one album like that before either changing away from my taste or trying too hard to meet my taste and it's never as good. Occasionally you'll get an artist who can make more than a few albums like that but they are very rare IMO.