Well I play the High lord mostly with classes that have warp or tactical cloak, so I guess I got a false impression. Neverheless a claymore X with just a high velocity barrel does 2k of damage which is enough to oneshot centurions/maraudeurs on gold and with some ammo and passive easily reaches the 3,5k which does the job even on platinum.
And you get a point for the reticle, let's just say then that the balance between accuracy and ease of use is just perfect with this gun 
But anyway my point was to say that acolyte just an easy to use OP weapon among many easy to use op weapons, and maybe the claymore is not THE easiest but there are lots of weapons which are just as "casual friendly" and OP as the acolyte.
I don't know where you're getting those numbers from, but to OHK a centurion/marauder on gold you're gonna need to deal at least 3.5 k of damage, if memory serves. So you either have a way of boosting your total damage bonus, debuffs and ammo included, to around 130-140%, or you need to land at least some pellets on the head. A GI is well in the 150%+ category, but many other kits are not, even if you get your hands on any available bonus. You're gonna need to blow dem melons to get OHKs with these other guys

I can definitely relate with the accuracy statement though, I love the Claymore's accuracy balance too. It hits the right spot. It's the main reason why I think the Claymore is superior to the Raider in most occasions.
I will also somewhat agree with the statement that there are many other easy to use guns. However, you have to agree that very few are, at the same time, as easy to use and potentially as abusable as the acolyte. Even the Venom, in all its ease of use and great potential, requires some bits more skill than the acolyte, as it's definitely harder to hit with it. It doesn't prime 100% of the times, and so on. The acolyte is just particularly easy to use, while maintaining a very high potential from an efficiency point of view.
Once you become really good at this game, there is basically no kit/situation in which it's gonna be the best possible gun, and that's probably what saves it from being broken as fu
ck. However, below that there is a huge skill range in which it's a good contender for one of the best possible guns on most of the kits/builds you're gonna play... And that, coupled with how easy it is to use it at its best, makes for a rather out of balance gun.
My 2 cents.
Well, perception is one thing, but reality quite another. Quite a few people seem to think the Harrier is OP, that is their perception. But the reality is that not a single first place entry in the Gold Solo Speedrun HoF thread has been recorded with this weapon (not even the TGI)..
I just want the damn weapons to have some semblance of balance in reality.
You seem to judge the relative power of guns and kits, and many other things, based on the solo halls of fame.
I would argue, however, that solos are not really the right compass when it comes to judge things in this game.
Simply because this game was never meant to be soloed. It's a 4 men co-op experience at its heart.
The fact that some people were able to successfully complete it solo doesn't mean that that kind of playing should be regarded as the basis on which to evaluate the balance of the game.
If anything, it's the opposite. You should not really keep what you see in those threads in mind, as they belong to a completely different kind of gaming that the vast majority of users of this game will never even think about.
Using solos as your basis for balance determination will lead you to some pretty incorrect conclusions, like (in my opinion) the fact that the harrier is far from being OP. While it is, in fact, very well in the OP realm, and is at least a good contender to weapons like the Wraith and the Talon.
In a 4 men team, I can assure you that there are at least 5-6 kits in the game on which the harrier is the absolute best fit of all the guns. And probably, given its jack-of-all-trades nature, about 30-40 on which it's in the top 3.
Obviously, if you're going to solo, the harrier ammo problems are going to be multiplied by an average of 4, making the gun rather impractical. But as I said, that's not what this game was designed to be about.