i love my raider. i cheated on him when centurion came out but i have found my way back. it's such a rewarding and impactful character to play but i hit a wall i had completely forgotten about when i started playing centurion; the slow atkspeed.

raider is slow as hell, he feels nimble because he can easily change direction of his attacks (pommel) and his fast dodge->GB, but his initial mixup that he relies on all start with a really really slow heavy. he can add some lights to this but these lights are fairly easy to parry and perhaps things will drastically change with how the lightparries will be treated in the upcoming patch assuming it goes through. but it probably wont.
the problem raiders have that slows down the gameplay is that at superclose range he dont have anything. anything he does will lose out to really fast attacks. he's not a shugoki, he's a big muscly dude with explosive speed who is for some reason afraid of frail little girls (pk's) who gets too close. one little stab will completely stop the momentum of his 2handed axe midswing, making the raider wary of doing anything at all when people get too close. cent and raider both have mixups surrounding their heavy. but centurions heavy is incredibly fast and can be used as a poke, therefor they dont have this problem.

i thought of giving him a faster attack to compete, like making his toplights faster. that would go in line with the idea that his sideatks are mixups and the occasional fast top (pommelstrike). but to give him a really fast poke might be too much. he's more of a hardhitting mixup character after all. so perhaps giving him armor on the latter half of his heavies, like the warlord? but this too i feel would be too much, yet i feel he needs Something to stop the raider from turtling up when people get too close.

-- so my suggestion is, change the uninterruptible armor to only be effective vs light attacks. and give raider armor on the later parts of his heavies. it will make it so those small dagger pokes wont stop all that momentum from a 2handed swing, and it will buff heavies by making them ignore the uninterruptible armor.
armor is a really annoying absolute mechanic that throws immersion to the side completely. i've always hated shugokis passive armor and how fast it regenerates.
berserkers will be able to spam his chains easier with the parry changes, but with this armor change he can't just ignore all incoming attacks and hope to trade. he'd have to make use of his dashcancels into light.