I'll be honest, I like the idea of this. The problem is, do you trust Frontier to keep releasing modules that are carefully balanced to not be overpowered? I simply don't have that level of faith in Frontier's game balance. They don't know how to balance a game, and they don't really try. If they keep doing this, sooner or later they're going to release a "required" module, the community will explode, and they won't even know what happened.
I'm not sure that they
can release a "required" module, though, with how the rest of the game works.
For PvE, the existing standard engineering modules are already overpowered for what you actually need - especially for the 99% of the game which isn't High CZs or Thargoid Interceptors. Even the ridiculousness that would be an overcharged + efficient weapon, if you only had one of it, wouldn't signficantly improve how much you could kill. I haven't bothered fully maxing out G5 on most of my existing modules, because it's not worth the time to gather the materials.
For competitive PvP (combat, racing, etc.), organised tournaments and events can just say you can't use them.
For competitive but non-organised PvP ... sure, this is where it could hurt, but ... there's already healing beams, premium synthesis, ridiculous shield booster stacking, half the weapons being basically useless, the FdL just being a little too good, half the experimentals doing nothing with shields up and something really bad when shields are down, etc. etc. As you say, they don't really try to balance things to start with. What difference is one more module going to make, when a few people are
still running around with legacy weapons from the original engineering? The game fundamentally isn't designed around it. (And ultimately so few people take part in this - because the game is already so badly balanced for it - that they might make a lot of noise when Frontier gives out a charge-enhanced+weapon focused power distributor as a CG reward, but it's not going to actually significantly affect overall player count even if half of them quit)
For uncompetitive PvP, one extra module again isn't going to matter - a reasonable multirole/trade build can escape but not fight back, an unreasonable one would be dead with considerably less firepower than existing ships have.