They tried the sanctioned thing with X-Factor during Alex's time as leader. It didn't work so well for them then. They really aren't the X-men with the government's help. The government has tried to harm them too many times.

This question is actually quite impossible for me to decide on. While I definitely don't feel like they should be disbanded, there are most certainly pros and cons to both being a vigilante team and being "supported" by the government.

Impossible to decide??? Give me a break, there would be very little or no "cons" at all by being supported by the government, it's the most corrupt origination there is that can't be trusted with anything. Being a private vigilante team would be the way to go.