I'm with Avaris. Earlier editions of GW games had formal systems of LoS that were way better for competitive play. I think the move to TLoS was to try to make the games seem more accessible (i.e. not falling back on a lot of rules jargon to establish what can seem like a common-sense question), but in practice it bogs down play and creates a lot of undesirable quibbling, particularly when as a company your model range is trending towards minis with more and more elaborate silhouettes and more and more spindly sticky-outy-bits...

In earlier editions, if my unit is behind a forest, or another unit of the same rules-defined size, you can't see it. Under TLoS the forest is interpreted as literally consisting of 3 trees and does nothing, and if you can squish your face down to the table and claim to be able to see one micrometer of the top of my guy's hat over the heads of the interceding models, you can shoot him. It creates more problems than it solves and it actively reduces the amount of tactics available with positioning and LoS, because hiding models from sight just becomes globally more difficult.