The only thing about it is to not let it become "Magicrun", where instead of augmentations, everyone just pays the mage for the proper Increase Attribute spell. Wouldn't be the first time I've had a decker player angrily announce that, rather than spend nearly 100k on Cerebral Boosters, he should just have the mage cast Increase LOG on him.
Mana barriers are an issue with Quickened spells, though not an insurmountable one (most teams will probably do some recon, then just smash-and-grab before HTR arrives).
The Karma-Nuyen-Karma rule is what makes it a problem, as it costs 1 karma or 2000 nuyen for the spell. If it gets disrupted, just consider that a small amount ticked off of what would otherwise cost you thirty times the price for half the effect. Especially when it comes to stuff like boosting Intuition (something the Rigger, Decker, and Street Samurai will all really want), or Charisma for the Mundane face... It's so painfully easy to have a magician just quicken it.
Like yes, I will absolutely pay for the spell formula, the instructor cost, and all the karma expended. 500¥ (Health formula) + 10,000¥ (5 Karma to learn spell), 3000¥ (Instructor with Skill rating 6), then 2000¥ for the Quickening cost.
15k nuyen, for a +4 to an attribute, with no Essence cost. Keep in mind, the cheapest boost augmentation can give is Muscle Replacements, which gives 2 attributes a +1 for 25,000¥. Do you see the disparity there?
Let's take this a step farther. I'm a mundane face with 6 Charisma, and I want you, ASAP, newly made mage character, to quicken Increase CHA on me. Here's the 15k above, and another 26,000¥ on top. Total of 41,000¥ nuyen, to give you the Karma to initiate for the first time. It is still more bang for your buck than trying to get an equivalent augmentation by far, and affects an attribute that no augmentations do. Then once I've made the initial investment, I can just pay 15k for a different attribute later. Say... Intuition, because literally every character benefits. Am I spending 2k per spell every other run when a barrier knocks them down?
Eh. Still probably less than the rigger is paying to repair the scratches on his van. And unlike the rigger, I can still play my role if I decide not to pay!
I don't know how to feel about this-- Is it a problem? Or is it just something minor that I'm annoyed about?
Seriously though. Tailored Pheremones go up to R3, and give less of a bonus (and it's restricted to smell-range) for over twice the cost. They also wouldn't apply to Instruction or Intimidation.
You can handwave it "in-world" by saying "magic is rare, tho" but in play, when there's always a damn mage because everyone likes them there's no reason this wouldn't happen!