I think its important because the Nexus phones were supposed to be tightly integrated with Google, and not having the source code means there is a disconnect. Without the code, updates may not be as quick as they should be, just ask Sprint and Verizon owners.
@MdXMaxX It's a developers phone, not a media users phone. If you want a phone with removable SD card, there are plenty on the market.
Ugh, I hate telling this story. I live in Manhattan, but work across the river in NJ, using the ferry to commute each day. The ferry has a really cool app, has the schedule, a bus locator, and the ability to buy tickets! So I have my monthly pass on the app, I always have my phone with me right? So one day I got caught in late meetings, and my phone just had no juice left. I didn't notice that the phone was dead, I was running to catch the last ferry of the night to get home. I walked down the dock to board the ferry, and of course can't figure out why my screen won't come on. They don't let me board the ferry since I don't have a ticket! There isn't even a place to buy a ticket, now I realize that I am not getting home by ferry. Maybe I can catch the bus? I head over to the bus stop and see that the next bus is about 45 minutes away, if its on time. Usually I wouldn't have minded the wait, but I didn't have my phone to keep me occupied! So because of my dead phone I had a miserable commute home. If I had only known that there was a good back-up battery for Android phones, that night would have been so different.
It's never a top of the line phone in terms of specs. When the GN came out, there were phones with better specs.