The issue is that the method you store kinetic energy in a coil by means that as you store more energy, it gets harder to store more energy, it's also nearly completely a function of torque... Think of a rocket weighing one pound trying to lift a rope that increases in diameter as it lifts into the air. Sure ten pounds of thrust will work just fine at first, but you're going to hit that limit eventually. Same thing with springs. Go wind an old-fashioned clock or a windup toy, note how you have to use more force as time goes on? Same principle, just a more linear to aid in usage (actual springs have a much more exponential curve from what I remember).
Actually not on discharge, on CHARGE. Gearboxes on discharge won't help you with the loss of charging/discharging. That's like hooking a transformer up to a discharging battery to try and charge another battery. Hook the transformer up between the charger and the battery, you'll be able to charge a bigger battery. There's nothing wrong with pumping a bank of engines into an industrial coil (heck, with Electricraft you can pump a very impressive amount of power from a large bank of low-powered engines into a single motor), so that hasn't been broken. What has been broken is the ability to take a steam engine pop it into a coil, wait for... some amount of time I don't want to figure out the math for right now, and get tungsten, repeatably, without having to make the normally required infrastructure for a gating material.
It's lowered the number of uses a bit, but not quite as bad as it seems at first. You can't use it to power things you probably couldn't power already anymore, but if you need a quick boost of power, but don't want to set up an engine, you can still do that!
