Diablo® III

So the follower skills are all availible at level 20. So what happens as you level up past 20? Obviously the skills they have will keep scaling, but for 40 levels nothing changes except the gear you give them? That seems just plain boring. I searched for this question on the forums but didn't find an accurate or satisfactory answer.
Also, how often can you change their skills, just at any tower along with your own skills?

I am not in the beta but I believe they get increased stats per level up and likely some of the stats on the skills will go up. I think the stats that go up would be things like the amount of life healed.

The other two followers will still get skills at higher than level 20.
http://us.battle.net/d3/en/calculator/follower