Wow, this is really lame.

I've probably nerfed my alchemy with all the different potions I've created.

You have got to be [censored] kidding me!

I'm going to use the console and a fresh character to run extensive in-game tests and verify this beyond a doubt. If it's true... all of my rage. If Bethesda did it on purpose, all of my rage +1.

FALSE ALARM, EVERYONE.

I just used the console to test every combination of 10 different Restore Health ingredients, first at skill level 24 and then at skill level 100. Every combination of ingredients improved from 22 Restore Health to 30 Restore Health at skill level 100, even after I'd previously used them at a low skill level. The only difference is combining Blisterwort and Imp Stool — for some insane reason, they yield 13 Restore Health at skill level 24, and 18 Restore Health at skill level 100. They actually do improve with skill level, though, even after having been used at a low skill level.

In addition, if you add a third ingredient to the Blisterwort and Imp Stool combo, the amount of Restore Health returns to the normal 22 (at skill level 24) or 30 (at skill level 100).

The only thing wrong here is that Blisterwort and Imp Stool together yield less Restore Health for some mysterious reason.

A difference of 76 levels yields an 8 point improvement in the potion effect? That sounds kind of nerfed to me...

Yeah, it's nerfed, but at least it's not completely broken in the way the OP suggested.

For the most part, skill level in Skyrim is only useful insofar as it allows you to unlock perks. You don't get nearly as much power from leveling the skill itself — for example, there's no difference between 1 Destruction and 100 Destruction, except for which perks you're allowed to take.

I'm at 60 Alchemy and making restore health 65 points. The best poisons I'm making are a paltry 59 instant poison damage plus 59 slow for 59 seconds. I'm not happy with the damage but the added slow is good. I think you need human flesh for the really strong poisons.

I did a lot of potion brewing yesterday. I made a ton of a particular potion, using the same two ingredients each time. My Alchemy skill leveled while making these potions, and the next potion in the set was +1% stronger than the previous ones. Did the same thing with a different potion, but no increase in potency when the skill leveled again. I'm on the 360 with patch. So the Alchemy skill seems to upgrade at least some potions for me; might upgrade all of them, but the second potion didn't get noticably stronger due to the way the fractions worked in that particular instance.

Yet to confirm if Perks are actually increasing the potency of effects on duplicate potions. If I get a chance to test that, I'll keep you informed (assuming someone else doesn't beat me to it).

Hmm interesting. So my impression is that progress in skill in general has only very little effect on the talent. The only thing that seems to count is the unlocking of perks.
I think i dont like this. The perks should be kind of an extra-kicker for special abilities, not virtually the only way to get better in something.
I would like to see a significant improvement of my talents by levelling up itself.
As i said. Perks only for special abilities not for general talent improvement.

This is incorrect in every way. I know because I made a huge number of restore health pots while levelling alchemy using only Wheat and Blue Mountain Flowers. This resulted in a mess of different potions restoring 22, 23 and 26 points of health as my skill increased while combining ONLY THOSE TWO ingredients over and over.

I'm at 100 and mine are around a 90-95 heal.