I think this might go without saying, but mod makers do what mod makers want.
Whether or not you like, dislike, or don't care about IC2-Experimental or even IC2 in general, to suggest a boycott is well, I'm not trying to be rude but it's overdramatic. The fact is, we don't pay money to the developers of IC2 to use their mod, they don't get any reward other than compliments like "Great job on the mod" or "Awesome mod!", a statistic on downloads and rarely they get donations to continue their work on the mod, donations which I doubt could sustain any human being in the modern world.
If you don't like a change in a mod, you can express your opinion that you don't like it, that's your right and no one should argue that.
But if you want to force a mod maker to make a change to the mod that he has made for pennies on the dollar with his own valuable time and shared with the entirety of the Internet for free you're beginning to push past what entitlement you do have.
My honest opinion here is that if you don't like a mod or how a mod's turned out, don't play it. Simple as that. If a lot of people feel the same and don't play the mod, the numbers will naturally reflect that, and it is the mod maker's decision on whether or not to make a change based on the opinions being voiced and the change in statistics.
You don't need organization, a group effort, a pledge, etc for your opinion to make a difference. At the end of the day, it's not our creation nor is it our right to tell a mod developer how to make his mod. If the mod maker wants to ignore an opinion? That's his right, he put the time and effort into it, and if he's fine with the drop in people playing the mod, so be it.
I'm not saying that people should or shouldn't play IC2-Experimental, but just the word "boycott" on something like a Minecraft mod is a step over the line. Whether you play it, or don't play it, like it or hate it, that's for every person to decide on his or her own. The mod maker is free to do what he/she wants too though, so long as he/she can deal with the results of their actions. For instance, I know Rotarycraft has been brought up, and I'd like to point out all the suggestions Reika has turned down to keep the integrity of his mod. Reika's more than willing to take suggestions (heck I've even made a few), but just because people would like it doesn't mean it's going to be done.
I apologize if this seemed like a rant, though I don't intend it to sound like one, I just figure I should express my thoughts in full on why I believe boycotting any mod is too far. Just play it or don't play it, and hope that the mod developer likes your recommended change, you don't need a group or a collective cause to do that. I personally quit playing with IC2 a while back, and like everyone who stops doing something I have my reasons of course.
So, I'll finish this lengthy post with a quote
"You can pick your nose, you can pick your friends, but you can't pick your friend's nose."