The weapon triangle was usually imbalanced and rarely had a meaningful impact on gameplay anyway, so IMO it'll be a healthy change, even if it's a bit jarring. There's still a lite version of the triangle in passive skills, learned through increasing weapon proficiency. See here:
https://serenesforest.net/three-houses/pre-release/skills/ Example:
Swordbreaker
Grants Hit and Avoid +20 when equipped with Lance and foe is equipped with Sword
I think it's just the nature of how the weapon triangle directed gameplay that I have grown accustomed to in most FE games.