[Stands firm, there's a perk for that, probably] Nothing wrong with the numbers in MW and OB. What I mean is, they could have made Alchemy more complicated, added in stacks off extra effects, loads of extra equipment etc. Extra depth, extra complication, some like that, some don't, but they didn't do that. Instead, this one really simple, easy to understand, easy to implement idea, by itself, has made the system just a tiny,tiny little bit deeper
Actually thats feature from Morrowind alchemy what I glad to see again but now it will be enhanced with perks.
At first, you will only be able to see one or two effects listed in the stats of any given ingredient, depending on your starting skill. Each ingredient can have up to four effects. (See the charts listed in the links below for more specific information.) The number of effects you can see will depend on your skill, based on the following values:
0-14: No effects visible
15-29: 1 effect visible
30-44: 2 effects visible
45-59: 3 effects visible
60-100: All 4 effects visible
Some ingredients have fewer than 4 effects, and you can always tell how many effects an ingredient has, because unknown effects will be listed simply as "?". However, while you may not see all the effects listed, you can still make potions with these effects. (A marked difference from Oblivion.) If two ingredients you have chosen share an effect, even one that is hidden to you, the Alchemy screen will still show you what that effect will be on your potion. (This is one way to learn the later effects of ingredients even if your skill is very low.)
Not sure if this is possible, has it been confirmed? I know you can put poison in other NPCs inventory while using stealth but if you put a potion that has 2 unknown effects and that NPC drinks it, how would you know what are it's effects unless it kills him/her? It's not like the NPC will give you a piece of paper indicating what it did to him..
If NPC will drink\eat it then positive effects is better then negative at last don't harm health magicka and stamina which NPC AI can avoid if item not a poison, additionally on consuming of such item can be VFX played on what we can assume what kind of effects ingredients has, or you can use mod like I use in Oblivion what allow see certain stats of NPC if player character win check for Attributes and Skills (intelligence more 50 + Alchemy more 50 for example allow see how stats change from potions and poisons in message box, I like experiment on caged animals and captured bandits, too bad devs remove useless for them but needful for modders attributes)