Is 1000 even realistic for everyone except a handful of people? I play every day and have every upgrade plus 45 extra teeth. Just doesn't seem possible for someone who plays 3 games a day. That would be roughly 10 to 11 teeth a day, 300 a month, 600 by the time it comes out on PS4. I think it's almost impossible to carry 3 noobs thru NF or Mayday due to boss in final battle. That leaves POC and Awakening to play over and over again. POC is boring now and Awakening will be just as boring after another 10 games.
I totally agree with you. Don't get me wrong, I'm glad the devs listened to the community and gave the hardcore players something to work towards, but most players will never reach that amount of teeth. The only way I see if being possible for the masses is to introduce another way to earn teeth. I'd love to see them introduce daily, weekly, and monthly challenges like halo 4 currently offers. Some examples could be kill a rhino with melee damage only for a daily challenge, escape 20 times for a weekly and kill 15,000 crytids for a monthly challenge. It would add some more interest to the all the grinding that will be going on over the next few months and also make obtaining 1000 teeth a little more realistic to every player.
That could be pretty cool, I like that idea of daily, weekly or monthly challenges like that. They'd need to have quite a few though. I guess they could also have "Get X amount of kills with X gun". They could make it gun specific, or gun type specific.
Just to add to this:
As you say, the 1,000 upgrade is for the hardcore players, those of us who are too addicted. I doubt it will be anything game breaking, if game changing at all (maybe a patch or a background, or something of the like). Just something to let us stand out from the crowd (although yes, we do anyway by the "missions completed" etc).