Of course the AR is popular. It's easy to use, reliable, and many players will choose to invest SP in it before considering a second weapon to skill into simply because of its simplicity and familiarity. You said it yourself, you're complaining about overuse and not imbalance. From my perspective, you're also wildly exaggerating.

Expecting every gun to be represented equally among the player base is pretty ridiculous. If I ran a poll of everyone's favorite ice cream, animal, cartoon show, book, superhero, whatever, not one of these would receive equal representation throughout. Why should random chance or even balanced weaponry somehow result in balanced diversity in weapon usage?

Less than half of my deaths have been the result of lone AR fire. Hell, if I'm going to escape from any fire fight, it will be vs an AR at mid range. I'm just as likely to be under fire from scrambler rifles and in my experience someone in my LOS is probably holding a mass driver or a flaylock. Snipers are abundant. Scouts usually have a shotgun, smg, and/or flaylock. Heavies are obviously likely to be carrying HMGs or forge guns. I don't see plasma cannons, maybe one a day and that guy's probably just trying it out. Don't see many lasers. I see them, but not many.

OP, I value your opinion, because you're a niche player like myself.
AR Spam is natural and expected, this goes all the way back to Counter Strike, even Quake.

The AR is everyone's basic starter utility weapon.
The scrambler rifle is my new utility weapon of choice, however. Learn to manage the heat, and it'll facerape ARs all day long.

When the other utility weapons come out, I believe CCP will change the racial starter fits to use that race's utility weapon.
Only Gallente will start with the AR, Amarr will start with the SCR, and so on. Then you'll see the systemic balance you desire.

Be nice if we had access to weapon variants at Standard level again.
STD Assault Scrambler Rifle, STD Tactical Assault Rifle, etc.

Where exactly are you getting this information?