Has to be external considering how many power supply failures the original Xbox had.
This is an assumption. We are now 12 years since the original Xbox debuted.
I bet most of you don't feel comfortable opening up the console to replace it if it were internal.
This is irrelevant. Most of us, regardless of whether it's a power brick or internal, would have to send the console/power brick/get a replacement.
External power brick is a positive.
Your argument doesn't seem to logically follow to this conclusion.