Iverson is still great and always has been great.
But he was a bad fit for Denver. Actually, Denver's team was a bad fit for everybody involved. AI and Carmelo could have worked given a better team around them. Issues at PG, issues at PF, and issues at Center really hurt them.
Bottom line is, it's not a full-blown rebuild, but they're trying to start over, at least it seems to me. Nuggets needed a true PG, and they got one. Billups IS aging at 32, but he has 3 years left and I believe he will play out his contract very well.
We'll see what happens with Nene. If he can stay healthy and if he can produce. We all know Kenyon was never worth the money, but at least he's healthy now. Carmelo is still a great ball player, he shoots at a high clip (anybody questioning that can just look up the stats, he shoots at a very hig % given he is a wing player/on the perimeter) and his rebounding increases yearly. Hopefully he can continue to improve on defense.