Butts would be great if it had the infrastructure and the scope and was feasible etc., but it hasn't, especially not since they have been building all around it. If it had been a few years ago, before all the new development, then yes, it would be a definite goer.
12,000 -15,000 is a worry to me too. If I knew we would just be hanging around League One, then fine, but TM has now built a side that has a realistic chance of going up this year. We would get over 20,000 for some Championship games for sure, especially if we were doing well.
When we were struggling and looked possible candidates for relegation, if we had have gone down then I would have said 12,000-15,000 would have been bang on and perfect for us for League Two.