To me, no. All of my basses have a pre in them, and I still use it. On my Bongos, for instance, sometimes I just want that little more low-mid content, and instead of having to go back to the FAS and edit my preset (and all presets, since I use several a gig), I can just dial up the low-mids right on my bass.
A lot of preamps, even with all pots centered, still slightly color the sound. You may or may not like that. But, not all preamps are alike, too. If you use ACG's filter preamps (which are similar to the Wal preamps), you'll have a different outcome than your standard EMG preamp.
Just as EQs on amplifiers don't make on-board preamps unnecessary, having a "do it all" processor doesn't, either. You may like the tone of the preamp, the center points and Q (which you can't easily figure out in most cases), or the way they load (or don't!) the pickups, the way the filters engage and move that you just can't really do easily on the Axe.