Not only is the Fender non-contoured heel uncomfortable (I realize some people never play past the 12th fret, put I actually utilize all the frets), but it looks completely out-of-place since the rest of the guitar body (such as a Strat) is so contoured. You have all those nice rounded curves and contours, and then right in the middle of it all, this squared-off block of wood. I hate it.
I totally like Fender's contoured heel on their Deluxe models, not only for their comfort and appearance, but for their simplicity. Just round one corner of the neck plate (if using a neck plate) , relocate one screw, and shave the wood accordingly.
I know it won't work on the Warmoth Pro construction, but all my necks have a top-adjust truss rod anyway, so it wouldn't be an issue for me.