"I just hold the button, and it makes the gun stronger :D" Doesn't really seem to do much for me. I mean, a lot of the charge weapons just become 1hko's so it doesn't matter that you can't rapid fire for the most part. Why not just charge it? To not charge it would just be stupid. What kind of depth is provided by something such as that?
And really, I get sick of going around a corner and suddenly a fully charged something gets let off in my face. It turns a lot of situations into no-contests.
Wouldn't it be better if after the gun initially charged, it started loosing its power so that the charge couldn't be held indefinitely? That way, in order to get the most powerful shot, you'd have to have to time when to start charging. It probably wouldn't make things much more difficult, I mean you normally have a pretty basic idea when you're going to get the opportunity to shoot someone, and it would do a lot to elevate charging from something shallow and brainless.
This might be worth experimenting with. If the game is fast-moving, it might generally be difficult enough to get off a charged OHKO as the guns are now. If without jumping the game is slower, OHKO guns will be overpowered and the delay might serve a meaningful purpose. But, to what extent is it right? What do you have in mind, OP?
I wasn't good with the SR,DA, or WP; so, as far as my experience can tell me, the guns are difficult to use. Obviously, there are people who don't have much trouble; so, they might be licking their chops at the prospect of playing in a game without crazy jumping.
I think the game will be a bit slower, but the SR has a significantly reduced magazine (or whatever the drudge calls them). Assuming the other two guns are nerfed (which they probably won't, since they weren't popular guns), the delay might not be necessary.
"It shouldn't do damage to you. If anything, the longer you charge it the more ammo it burns."
That would work really well! But I kinda think it doesn't have the same reward of getting the timing right for full damage. I kinda like the Idea of having it do 20% or more damage for just a few frames the instant it finishes charging, and then holding a normal charge after that for a few seconds before it starts degrading. That I think it will help people interpret it as a reward, not that they're simply being punished for holding a charge too long.
As for visual cues, I'd have the gun spark a little, and have a small sound effect to go with it every time the charge stepped down in power, a really unobtrusive indicator.