These threads come up about every year or 2; yes I did some searching with different terms to verify. The responses are always the same: don't do it.

I think I've done a few tight connections (under 45 min) at both PHX and CLT over the years. If memory serves, even one at LAX, but I ended up being on the same aircraft so lucked out.

At PHX, many people do these connections almost every day. At a hub with mostly good weather most of the time, the main hiccups are an aircraft blocking your gate (happened to me), the moving walkways not working (I don't think I've ever seen all of them working), and other passengers being clueless and standing in the way.
For CLT, you can, and usually do, have weather much more often. If you are going between mainline and express...well then wear running shoes and hope for the best. It seems I always arrive at the end of B and leave from the end of E, or the other way around. There are very few moving walkways, and there are tons of clueless people standing in the way.
I did have at least 1 tight connection, F to B at PHL once...not through my making, but because of a late aircraft. Thankfully we pulled into one of the gates at F close to the terminal, and I just ran, and made it. I didn't want to take my chances on the bus (at least it was after there was a connection when I had a choice).

We have threads specific to each major AA hub (and even non-major hubs). I'd take a look at the appropriate thread, read recent posts, success rates, perhaps post in that thread with specifics, and go from there.