I've heard conflicting Information on if Followers actually level up with you or not? Was this a bug....has it been fixed?
Do we know officially if they level up or not? (Im specifically talking about Aela (who im going to marry) so im trying to see if she will level with me or not.

Don't know if they are leveling or not, but there are two ways to fix this issue. If you are on the PC, you can disable then enable the follower. If you are on the consoles, you can use Wabbajack, turn them into something, hit them, let them come back to human and they are leveled up.

I stopped worrying about this once I found the ways to fix it.

I guess you'd have to disable/enable everytime you level up eh? lol

One reason you might not be noticing the level, is that level has very little to do with damage output or protection in the player character. Most of your output comes from perks, which your NPCs don't have access to.

But that's not the main cause of the problem of unimproving followers.

Followers never get their skills or stats recomputed. If you find a follower at level 10, its stats are computed as that of a level 10. If you find a follower at level 20, its stats are computed as that of a level 20. But if you find a follower at level 10 and then you get up to level 20, your follower's stats are never recomputed - though your follower is technically labelled as a level-20 character, his/her stats are still exactly what they were at level 10.

PC users have long had a means of rectifying this. Thanks to CCNA above, though, for making me aware of a way to rectify this on PS3/Xbox360. Very useful. Maybe I will be able to get Lydia out of the kitchen again after all.

No, about every 5 is all you really need. You don't notice your followers "falling behind you" in a fight until they are 5 to 10 levels below you.

If I try the Wabbajack approach with Lydia, will this cause her heavy armor skill to increase, resulting in her no longer wearing the super hot Forsworn armor (light armor) she currently uses?

How many times are you going to hit her?

Her stock armor is not that good and if the Foresworn is improved, she will probably wear that over her stock armor.

if they're having a hard time with a skeever, you know you're in trouble! And I've actually seen that with Lydia before I raised her level

Followers not leveling. Lydia still not marriagable. Still can't get the house in Windhelm. I swear I've yet to figure out what that last patch fixed.

Do not despair! Scuttlebutt has it we'll be seeing a high-res texture pack released alongside the CK! Who cares about game play as long as my screen shots look shiney!

Until she brings me my dang sandwich!

I hope that's not it. My PC is giving me the PINK textures now just from a very few texture mods. No way I could use a full texture overhaul without a new PC. I would much rather the game get all these SIMPLE TO FIX bugs smashed and Bethesda not depend on the users to make 'unofficial patches' to fix them. Besides that's hardly fair to the console users.