re: Does anyone seriously believe that there are 12 legitimate contenders in any given season?

There were only 7 this year - if you stretch it - assuming no opt-outs and Travis not injured.

That is probably the long end of normal. Most years there will likely only be 3 to 5.

But teams 9-12 are closer to teams 5-8 than 5 through 12 are to 1 through 4. In other words, first round games will be interesting but second round will be dominated by top 4 seeds. Semis will be hit or miss in competitiveness.