Let me clarify. As I said twice in my original post, we had a great time. As far as the vacationers from Louisiana, I don't blame them one bit for being there. If I lived in New Orleans and the kids had a week off school, I'd choose that week to go to Disney as well.
But the crowd levels were a bummer. MK was swamped on Monday and EMH on Wed night had minimum 30 min waits on most rides in Fantasyland. We like to go in late Jan or early Feb to get away from the long Minnesota winter, and because this is a slower time of year in the parks. Bob Sehlinger's Unofficial Guide called for crowd levels of 3 (out of 10), meaning light crowd conditions for this week. I also didn't see any discussion on these boards about the increase in crowds at Mardi Gras, but I may have missed it.
If Mardi Gras falls in late Feb or early March, the effect on crowds probably won't be noticed, since it's busy then anyway. But in early Feb, it probably doubled the attendance in the parks.
In the future, if you're deciding between late Jan and early Feb, and Mardi Gras is involved, I again would say beware Mardi Gras week, and go in Jan. I will.