I love rationalizations!
I do think there is a scenario where the 3rd seed could be good though.
I think the first round is irrelevant. C's and Heat are both going to cruise to the second round.
However, I really believe that Miami's success and demise in the playoffs will be directly related to their emotional and mental responses to playoff basketball. I think if they are able to get come confidence going against the C's, they are going to be a really hard out, while if they are knocked down early, I am not sure they will get up.
Now, obviously, having home court in the first two games would be very helpful in knocking them down early. But the downside of that is that they then get to go home, and have another chance to resurrect themselves, and get the momentum back. However, if the C's are able to go into Miami, and take one or both of those games, they will have a chance to really step on their throats in games 3 and 4 back in Boston, and I don't think Miami is mentally tough enough to come back from 3-0 or 3-1.
Now, don't get me wrong, I still think we are better off in the 2 seed, because the game 7 at home is a huge advantage. But I can rationalize this with the best of them.