It makes alchemy a discovery experience.
I can't remember anymore, wasn't that how Oblivion was, or was it all discovered already? The discovery process DOES keep it fresh. It's just trapped within Bethesda's very tired system. And because there aren't visible stats anymore, there are somewhat fewer potions. (Although maybe they're replaced by a few new ones, like Fortify Blacksmithing.)
I dunno. The system works and its clean. But compared to Witcher's alchemy, Bethesda's alchemy has always felt tacked on. If they'd be willing to break out of their freaking rigid design and let alchemy (and magic) do something novel like they used to, the system could be so much better.
Honestly the only reason I bother with alchemy in Beth games is because of poison. Especially now since it's actually fair to use it when you're going up against Giants who can crush you flat in one shot. Using it in Oblivion was kind of overkill.
It is also totally free now and has a skill tree associated with it.
Except you're stuck creating boring, one effect items for almost the entire game and it's completely based on what gear you find. Whereas you could buy spell books in Oblivion at or around your own level to get a plethora of effects, here you're stuck with the handful of stuff you decide to disenchant. I much preferred Oblivion, and I hate the fact items are one effect deals. You could do more in Oblivion and I don't get their rationale here at all. Unless they didn't want player created items stealing the thunder of the stuff they gave you. Which would be easy to do, because the items I've been getting in Skyrim are booooooooorrrrrriiiiinnnngggg. Tons of Soul Trap weapons, a few of the (three!) elemental weapons, some armor with fortify this or that. I'm still using the Frost Sword and Fear dagger I created _at level 5_, because I simply haven't found anything more interesting to use and there's physically no way to create anything better!
Compared to the Boots of Jumping, there isn't anything in Skyrim half as cool or inventive. And you can't even make anything good without disenchanting/enchanting crap items all the way to 100 skill.