Admittedly, I only have interacted with three followers, of which only two are not level locked, Lydia and Erick the Slayer.

I'm level 27 atm, and I met Erick when I was 25. Back then I was hanging with Lydia, whom I met when I was a little over lvl 20. She was then as now, lvl 25. Lydia was always a squishy liability. Went down almost as fast as she got into a fight and more often than not I had to get out of my way to baby sit her.

I never thought much about it until I met Erick. Upon checking his stats on the console I was awed. At the same level as Lydia the guy packed 430 health 130 stamina and well over 50 in two handed weapons, whereas Lydia had exactly 158 health 67 stamina and really low weapons skill. I hired the guy on the spot and gave Lydia the middle finger.

Somewhere down the road though, I started to ponder about this astronomical difference between them. Being after all at the same level, there was no reason for it. Upon searching on the web I quickly found out that some followers are supposed to level up with he player. And I noticed Lydia's stats are not only incorrect for her level but completely off. At 25 Lydia is basically a lvl 1 NPC.

So this is my situation, A completely useless NPC with broken scaling, Lydia, and another that while scaled properly for it's level, isn't leveling up with me.

Do you guys have any insight into whats going on ?

Thank you.

You could try the Wabbajack trick. But you being on PC, I'm sure there's an easier way.

well if by Wabajack trick you mean firing the Wabbajack at them, I just tried that, sadly it didn't work. I've also tried disabling/enabling them on the console as well as dismissing them. No use.

Thanks for the suggestion though.

I had several follower mechanical failures and installed http://skyrim.nexusmods.com/mods/15524/?. I can't see playing without it ever again. The sheer versatility is unbelievable.

No more issues of any kind and better...

AI

leveling

armor

weapon usage

charge weapons

combat strategies

trap avoidance

and the list goes on.

+1 for AFT. I started using it when I got antsy waiting for UFO to add Dragonborn support. (Teldryn Sero FTW!) Haven't looked back. It's on my list of "always use" mods, right up there with SkyUI.

(Plus being able to zap NPCs with the AFT power and take over their lives leads to all sorts of fun hijinx and shenanigans. )

The mod works great as far as I tested. I don't know how I haven't heard of it before. Loving the new features.
While I could manually update the stats of my followers, setting it up back to "automatic" didn't reset their stats to what they should be, but to the original flawed values. This makes me think the issue is far more severe than a simple glitch. I will continue to investigate further. Manually leveling all my followers at every level, seems like a very heavy burden

For the time being though, I can make Lydia as powerful as she should be. Or even more, since I can optimize her build and spend her skill points more wisely. Plus I can have her + Eric following me. How cool is that?

Thank you!!

http://skyrim.nexusmods.com/mods/14037/? (Ultimate Follower Overhaul) scales up followers with a single menu option, too Although it seems to be outdated...