I don't know what is causing those splits, but they might not be problematic. Some trees have bark that fissures vertically as it ages. Others here with more experience can address that.

My clarifying question is: What do you mean when you say "before you read about all the problems it has"? I am not aware of any problems with AB Maples....

It just seems whenever I read a post about tree recommendations the AB gets more blasts than approvals...bark splits, poor branching, lousy fall color and just a general disliking of this tree. I have read that it has an agressive root system and that it doesn't have an agressive root system. Don't really know what to believe anymore. Just know that I like my tree and don't want to lose it.

Deb, i had or have pretty much the same exact comments and even the same question as ddifranco just now. 'Autumn Blaze' is a great tree. Certainly not a "plant it and forget it" type however, due to many V-crotches and competing leaders. But it's a very valuable workhorse type of tree.

I agree also that this bark fissure may indicate little more than tree growth. This is not a fussy plant, in any way, albeit, for long life in the landscape, some careful leader training or subordination pruning should be done in its youth.

All trees have "aggressive" root systems. Maples perhaps a bit more than say, some slow-grower like Japanese tree lilac, to swing this thing all the way to the opposite end of the spectrum, but so-called aggressive rooting is simply the plant doing what it does. It's not as though that is somehow a defect.