If you like hard buttons, stay with the Mogul...
If eye candy is not a big deal, stay with the Mogul...
If you like running out of RAM every so often, stay with the Mogul...
If you like running (jogging) when you have apps open, stay with the Mogul...
The battery issue depends on the tweaks you apply to your phone...my TP actually has BETTER battery life (i consider myself a moderate user) than my Mogul. I like being able to multi task...and for the TP not to blink an eye. I missed my buttons for about a sec...the VGA screen eases a lot of pain of losing buttons.
Touch Pro 2 IS around the corner...and the Palm Pre as well, I think whoever mentioned that is right...wait and a good hard look at those machines as well.
If you are decide to keep your Mogul...I suggest you flash to a custom ROM (if you have not already done so) to get better usability out of your out-dated machine.