I think the spears in the game are cool, and I like using them–especially as a projectile.
That said, the primary attack could stand to be more interesting and less annoying (as others have said).
After reading through
Polearms would remain viable for the spin attack extra reach.
Another idea is to add a 'bracing' stance (maybe when holding the primary attack button) as an alternative to simply blocking. This would perhaps disable parrying while active, but cause damage to a charging opponent. I can see this being useful against animals.
Maybe these are perks added to later spears, to encourage upgrading.
Source: https://www.reddit.com/r/valheim/comments/10kbja4/spear_some_change/