One thing that I had forgotten was the flatter bonus curve for ability scores. Let me highlight--this little "chart" will have the ability score, the bonus in a Moldvay environment, and the bonus in a d20 environment. m20, for what it's worth, tends to follow the d20, not the Moldvay, paradigm.
I also have to think about the range and distribution I prefer, since seeing the Moldvay range and distribution, and realizing that it makes a much better bell curve, has got me second-guessing what I've done with d20 and m20 for the last fourteen years. And finally, I'll have to think about how racial stats interact with any choice I make.
For those who care about the details of my m20 system (that is, just me) stay tuned here... as I noodle around these issues, there may be minor updates in the document.