[Lesion] is by far one of the best polearms in the game, that is not something that anyone can doubt. However, something that I can argue is... why has no one tried to push Status chance into the stratosphere with this weapon? It's absolute begging for it, and being able to proc Status on Status on Status is hilariously funny with Bleed damage.

Additionally, everyone I've ever seen builds Viral super high on their melee weapons because they want Viral to proc... before? If you look at [Lesion]'s passive, it states that it gives a Toxin buff temporarily for each successful Status proc. The only two Statuses we have on the weapon of note are Cold and Slash. Because of this fact, the Toxin will combine with the Cold to give us a Viral buff that is lower than our Slash, meaning that it successfully allows us to build up our Bleed and then have it benefit from the Viral, rather than the other way around...

Anyways, you could definitely swap [Melee Prowess] or [Boreal's Contempt] for something like Berserker's [Fury] if you're worried about the Attack Speed reducing your DPS, but remember that the Passive also gives you a free .15 which is still faster than most hammers.

Anyways, at max, the Slash damage should be giving you tons of damage with reliable Cold, Toxin, and Viral procs to help further support you. If you're doing something with Infested? Swap to Heat and make it a Gas attack. Grineer? Swap to Electricity and make it Corrosive for their Ferrite armor.

Also, this isn't necessarily "late-game viable" (although it certainly could be), it's just something to help you [Shred] down targets with a thousand tiny cuts rather than one big, chunky hit.