Google Wallet isn't part of AOSP (The Android Open Source Project). It's included with the Sprint Nexus S 4G (which is the only phone to offer Google Wallet without hacks) because of some sort of deal between Google and Sprint that we don't like, understand, or really know anything about. Come to think of it, the same thing can be said about Google Voice integration. Why Sprint-only, you ask? Like I mentioned, we don't really know, but Google needs somewhere to test these things and Sprint was willing. Let's be clear here -- no other Nexus device has ever had Google Wallet without hacking it on. This means the Verizon Galaxy Nexus is just like the penta-band unlocked GSM Galaxy Nexus in this regard. Or any Nexus S that's not the Sprint Nexus S 4G.
The MyVerizon app and some backup assistant app aren't part of AOSP either. They have no business being on a Nexus device, except for one thing -- both are "required" for Android devices on the Verizon network. Them's the rules, and even Google will follow them. Contact backup assistant is there because Verizon doesn't want to be swamped with phone calls about people not being able to migrate their contacts to Android. It happens more than we think. Lose backup assistant, and spend thousands in unwarranted tech support. Verizon is too smart for that (you don't become the top carrier in the U.S. unless you're smart and a tiny bit evil) so you bet your ass they are going to cover all the bases they can.
MyVerizon is now needed because we live in a time where unlimited data is slowly phasing out. Verizon went with tiered plans versus bandwidth throttling, so they are obligated to let you know exactly how much data they say you used. Remember those class-action suits where Verizon had to pay every person on earth $12? Verizon doesn't want anything like that to happen again. Just as important, current Verizon customers need to be able to have access to apps they purchased through the Verizon area of the Market and Vcast. MyVerizon helps authenticate those phones so they have access to them. Just because you will root and remove MyVerizon and never use VCAST doesn't mean everyone else will.
Finally, theres the matter of updates and inclusion in AOSP. Google will write all the updates for the Verizon Galaxy Nexus. Read it again if you need to, let that sink in for a minute, then we'll continue. Yes, there will be a bit of extra testing involved with each to make sure the Verizon apps work and that network specific code works as written, but we're talking minor differences, not weeks and weeks of delay. Nobody really thinks Sprint or T-Mobile or AT&T has no hand in network testing on existing Nexus devices do they? Any delay in updates will be small, and still miles better than the Fascinate fiasco.