Here’s the thing: without the layered power systems, it’s much less likely that we get talents “tilting” in favour of one thing or the other to the degree they have in the past three expansions.
For example… in isolation, my Stormstrike talent might be 5% behind the Lava Lash talent. Now we layer in a legendary system that could potentially buff my Stormstrikes by 70%, whereas the Lava Lash legendary only buffs my output for AoE. Now I’m locked in to the Stormstrike talent and Stormstrike legendary because of this layered power.
When the difference in power is well over 50%, it’s not a choice. Even if I play badly with that particular build, it is still going to perform better than the one I prefer and am better at.
But when we’re only touching talents? Tighter balance is possible. Perfect balance is never achievable, but tight balance is.
Now let’s revisit that 5% variance. I might simply suck with the simulated optimal choice, or I might just not like that playstyle at all. Choosing the “better” talent wouldn’t do anything for me, here, because I’m not going to perform as well as the simulation. It makes that “worse” option viable.
Now let’s make it even more interesting: what if the “bad” choice favours haste, whereas the “optimal” choice favours mastery? Now we can actually make decisions about our gear to suit our build and compensate for a “bad” talent with gear optimization.
In short, when you’re not juggling talents and legendaries and shards and Azerite and artifacts and corruptions and whatever else, you don’t encounter these exponentially more effective builds that render everything else moot.