Not sure what the issue is with polearm rightswings when compared to the strong swings from other weapon types. Each class has the ability to insta-swing/hilstslash. With poles it is easiest with the rightswings, with 2handers it is easiest with the left swing (I think, it's been a while since I played 2hander), and with 1handers it is obviously easiest with the leftswing. The only difference here is that the polearm rightswing is also the longest ranged attack direction for a polearmer, while with a 1hander and 2hander the rightswings are longer than their easy-to-hiltslash-attack, the leftswing. However, I don't particularly see the issue with having one animation that is the longest and easiest to hiltslash with because you can only do one or the other. In order to hilstslash you need to be facehugging, therefore it doesn't matter what range that animation has. Sure, it would be great if the polearm leftswing were perhaps tweaked to make it more viable, whether being long-ranged or easier to hiltslash with to entice us to use it over the other swings, but right now the polearm rightswing makes the class balanced with the other two melee weapons. However I will agree that since polearms really only have one good attack direction, spicing things up by offering more alternatives would be much appreciated to keep combat from getting stale.
The issues with the other swings (imo) are that the overhead has shitty hit detection, the leftswing is the opposite of snappy and also short-ranged, and the stab hitbox, ever since all stabs were tweaked, simply hasn't lined up with the animation all that well. To make matters worse, a lot of polearms actually have really bad stabs. Only the spears/poleaxes (or any 2directional pole, really) have a strong enough to stab to be somewhat reliable. Even the bec can have a really questionable stab, not to mention all the axes, maces, bardiches, etc. that have very weak cut/blunt/pierce stabs that are hard to land on anyone with decent armor. Compare the polearm stab to the 1hand stab... which glances more when using a weak stabbing weapon, like a mace? Those 1hand maces almost never glance compared to their larger polearm counterparts despite the fact that their stab damage is very similar. Now I'm not saying that literally everything about polearms except the rightswing sucks... but pretty close to it. The other attacks are very situational.