If anything I'd say it's underbalanced, from a group optimization standpoint.
- 1 IP only really works if your action is lobbing stunballs or ends with going astral or VR 9 times out of ten.
- 2 IPs is fine, you'll go more often than most of your opponents, most of the time and won't have your movement cut to peanuts.
- 3 IPs and you start to get into iffy ground. You're either slow as molasses from having movement split into 3 segments or tuned up with a bunch of speed enhancing qualities and augments to make up for it. You burn through ammunition like a wildfire in a matchbox factory. More actions per Initiative means more oportunities to glitch, fail, or try something challenging, so edge goes more quickly. Diminishing marginal returns start to rear their ugly head.
- 4 IPs. You don't really need this many (and in hindsight, I don't want this many on Jolly all the time). Every factor that impacts the diminishing marginal returns at 3 IPs is made more severe and more pronounced at 4. You're slow as molasses (per IP), burn through ammo like you're shoveling it into a furnace, and will have so many more opportunities to either need or want to spend edge that you'll be out of it in no time.
On top of the diminishing returns, not only does it eats up a lot of your essence and there are other ways to go about getting more passes that are arguably better investments like you mentioned, but the in character consequence of experiencing the world faster than normal would be downright draining (and probably part of why it's such an essence drain). Having active wired reflexes is how I would describe as being dysfunctionally high on speed, constantly. Sure, you as a player have the absolute power to play it as if you've gained reflexes and the ability to clearly think through and rationally process all of the input, but that's not exactly what the fluff seems to be. It'd be like having a body that reacts faster than you can think about things, should lead your character to some impulsive moments (not the same as the poor self control quality, but acting before you're able to clearly think your way through a 1 second or fraction of a second of a combat round), and leave you feeling like your thoughts are racing but can't all necessarily keep up with each other (kinetic synapses much more responsive than creative and rational).
Wired reflexes are a double edged sword, in RP terms, if you're one of those RP heavy sort of role players, and a mixed blessing at best mathematically.