I remember reading that certain followers don't level up with you. Is this true? I have never used a follower beyond 10 minutes (Lydia kept running into the same trap over and over again), but I had a RP idea so I need to know if they really are bugged.

Bumper stickers.

Best you try reading one of the wikis about them. They have some issues, but one can live with them. http://www.uesp.net/wiki/Skyrim:Followers

Just use a follower you have only recently met for the first time. They will be at the level you were when you first entered the same cell as them (some have a cap at level 30 or whatever, but you can always give them smithed and enchanted gear to improve their effectiveness).

I'm kind of amazed at how poorly Bethesda designed aspects of this game.

From UESP

The Wabbajack can be used to reset your Followers, allowing their level and stats to scale with yours, or reach their max level. (Xbox360/PS3)

To do this: Take your follower to a secluded area, save *since it can kill them or turn them hostile*, then Dismiss them, then use the Wabbajack on them until they transform into something, punch them to break them out of it, then this will cause them to respawn which will fix their lvl and stats.

Followers need to be looked at because of a few bugs (bow & looting issues i.e.), but they are otherwise fine. They are new to TES and I find them pretty cool. I did not expect them and their abilities are amazing (to use the same word). People want them to auto-level so they have a wider variety to choose from, but one can say Good-Bye to one and find a new friend as one progresses through the game. It is a matter of taste. One is better for immersion, the other is better for combat. When they get in your way should one not expect of them to read one's mind - they will never be perfect. Just park them somewhere and pick them up later.