I think it's also worth mentioning that WW and OP only get 1.7 x AP bonus with daggers, while the other items get a 2.4 x AP bonus.
While WW and OP are not exactly your biggest sources of damage, the fact that they have daggers have less weapon damage per swing and they generate less damage from AP makes it harder to justify the increase it auto attack damage.
If a weapon does 200 damage and the warrior has 1000 AP and the modifers are 1.7 with daggers and 2.4 with sword/axe/mace, WW will hit for 321 with daggers and 371 with 1 handed mace sword/axe/mace. You add the fact that a slow weapon will do more damage and there's a difference which i'm unsure if the increase in auto attack damage can increase.
Spamming HS 100% of the time is unrealistic unless you're MTing or on Vael. Even then you wouldn't due to threat.
I don't think daggers are outright bad, but after 11 years, if daggers were better than sword/axe/mace, people would have found out by now.