Would it be mechanically broken to put Holy Avenger on a Polearm?

[Levism84]

Sorry for all the polearm-based threads as of late.

I was wondering if it would be mechanically broken to place holy avenger (normally only swords) on a polearm (like a glaive or halberd)?

For a paladin that specializes in polearms, I figured it might be thematically appropriate, but I am not sure what giving a holy avenger reach would do exactly. I am seeing this as potentially being used to fight off hoards of fiends or undead with Tunnel Fighter (UA: Light, Dark, Underdark!) and the Polearm Master feat. Dealing an extra 2d10 radiant damage with an unlimited number of AoO against targets that enter with in a 10-foot radius might be divine overkill. I know the DMG states you could swap out damage types for certain weapon enhancements (fire for cold or thunder), but what about slapping a weapon enchantment normally reserved for swords onto a polearm?

[Tenmujiin]

Sorry for all the polearm-based threads as of late.

I was wondering if it would be mechanically broken to place holy avenger (normally only swords) on a polearm (like a glaive or halberd)?

For a paladin that specializes in polearms, I figured it might be thematically appropriate, but I am not sure what giving a holy avenger reach would do exactly. I am seeing this as potentially being used to fight off hoards of fiends or undead with Tunnel Fighter (UA: Light, Dark, Underdark!) and the Polearm Master feat. Dealing an extra 2d10 radiant damage with an unlimited number of AoO against targets that enter with in a 10-foot radius might be divine overkill. I know the DMG states you could swap out damage types for certain weapon enhancements (fire for cold or thunder), but what about slapping a weapon enchantment normally reserved for swords onto a polearm?

I'd have it not apply to polearm master's bonus attack but otherwise there is no issue I can see. (The only other way to get the damage on a bonus attack would be great weapon feat (I'd probably also have it not apply here) or getting two 1 handed holy avengers