The Chager is definitely a good weapon. Once you know how to use it both to kill enemies and spread ink, you can do really well. I looked at the guide they have here and implemented it in the testfire and I won a majority of my games. I even won against a team with one of each of the weapons you can choose, while my team had three Chargers and a Roller. When spreading ink You should only charge it enough to cover the area. Do not fully charge the shot just to cover a small line in front of you. Take advantage of long lines of site to cover as much ink with the fully charged shot and use quicker shots to cover a small line ahead of you. When fighting enemies, pay attention to the reticle, when you see an X through it, it means you will hit the enemy. Take advantage of your mines. Use them to take out enemies you can't shoot because you can't get an angle on them. If they are below you, you can throw it at your feet and it will bounce off and fall down to their level. If they are above you then throw it so it arcs onto their platform, or bounce it off a nearby wall. If an enemy is headed toward you and you can't charge up a shot in time, then throw a mine at your feet. Know when to retreat. If the enemy is getting too close for comfort, then hop into squid form and retreat. Distance is your friend, you can shoot the enemy, but they can't shoot you. Take advantage of small alley ways, the enemy won't have anywhere to move to avoid your shot. This is everything I've learned from playing the Global Testfire for an hour with just the Charger.
TL;DR: I do not think the Charger needs any form of buff. You just need to know how to use it properly.