There are arcanyst cards for healing, buffing, reducing the cost of and copying of spells, as well extra replacements. The Scientist requires having minions and spells that can specifically buff them to generate cards which isn’t the greatest.
Personally I think there should be a neutral arcanyst minion that should be able to in some manner pull specifically only spells from your deck. The spell it pulls would be random but it would be a spell that you own rather than L’Kian’s random faction spell. Since most minions that are utility based are valued at 3 or 5 (versus tempo minions at 2 and 4) it would look something like this:
2/3 for 3 Mana
Opening Gambit: Draw a random spell card from your deck.
Having thought about it further I think the game needs a keyword that allows minions to activate certain abilities at the cost of Mana. Call it something like Grease Palms. For the Librarian example it could be something like: Grease Palms: pay two mana and draw a random spell from your deck. Exhaust this minion. Make it so minions can either activate Grease Palms or attack but not both.