On the north side, the 757-300s replaced higher paying DC-10s when Anderson was in charge. Pattern?

A while back on a very early flight I listened to a minute long speech to ATC from a CAL guy explaining why it was taking him so long to get to altitude in his shiny new -900. Apparently it's ridiculously underpowered. I was on one on a mil charter from Vegas to SC a few years ago. We did a fuel stop in Texas! Must have been some extenuating circumstance that I didn't know about in that case, but it still sounds like a pretty poor 757 replacement.