Shock and Awe/Analysis

Required Secondary Powers
Unfortunately, one of the coolest powers is a good deal more difficult than pointing your finger and watching it go. If you want to splice together a pet Pikachu, you need to overcome these hurdles first:
 * Electricity has a tendency to take not only the path of least resistance, but to a lesser degree all other possible paths as well. Hitting your target without inundating everything around it with current would require a great deal of setup, meticulous planning, prior knowledge of electrodynamics, and the resulting hours of linear algebra to ensure that all other available paths are sufficiently resistive enough not to cause collateral damage. Here's hoping you're really Good with Numbers.
 * It takes a stupefying amount of energy to break down air and channel a lightning bolt. Before anything happens, find out how many meters are between you and what you want to hit. Multiply that by 3,000,000. That's how much of a voltage difference you need to generate without leaking electrical pressure into your surroundings. Again, sustaining the bolt means sustaining that voltage difference in spite of massive amounts of charge leaving your end. Good luck.
 * Of course, electricity is just the flow of electrons. A character who could control movement of electrons wouldn't have to worry about power output; if they can prevent discharges at will, could as well gradually accumulate static charges to spend later, all at once or in small doses. Many electrically-powered characters that are shown having to "charge" from sources of electricity probably work this way.
 * But then again, electrons don't really like being all by themselves, even more so if you've got a bunch of them together in a theoretical container. So a character keeping a bunch of "extra electrons" in their body would be constantly trying to keep them all neatly packed together. That's not even mentioning the effects all these negatively charged particles would have on quite a few very important physiological processes.
 * Natural lightning is a quick flash, a resolution of charge differences a fraction of a split second in duration. To strike something with a sustained arc means you have to complete and hold a circuit that is pumping vast amounts of current through your target, the air leading to it, the ground leading to it, and you. Naturally, one hopes both you and the ground are able to withstand this.
 * Lightning generates a lot of heat even in a quick flash, enough to fuse surrounding soil into glass. Sustained arcs are terrifyingly hot. Unless you want to melt your own flesh to gory slag, you had best pick up a fireproof perk as well. Even then, you'll want to turn off the juice before you kill everyone in the room via heat exhaustion.
 * Lightning is extremely bright, as anyone who's used an arc welder can tell you. Unless you want to reduce your retinas to gory slag, this is another good part to reinforce.
 * For anyone standing close to the line of lightning, visible light would be among the least worrisome parts, and even hard UV not much worse, as even in modest interpretation, it has to be many orders of magnitude more energetic than common electrostatic sparks and welding arcs to get proportionally greater range. Since this discharge happens in the air, it's going to produce an expectable bouquet of ions (and possibly electrons) linear acceleration itself churns out and what this does to the medium — the shower of braking radiation and perhaps products of electro-nuclear reactions (collisions between accelerated particles and everything in their way hard enough to break something).
 * And once you get past all that, where is the energy coming from? A sustained bolt takes one Hell of a lot of it.

It is possible, depending on the context, that the lightning-user channels it remotely - not through themselves. Many of these problems can be resolved if the electrical circuit is confined entirely to the target's body. But then you lose the cool lightning bolt, and all you get is a bad guy spasming violently like a deranged marionette until his insides boil out through his skin. Although, if Mr. Lightning controls electrons themselves, he should also have the power of disintegration, as electrons have the wondrous duty of bonding atoms together.