I'm of the opinion 36 binds for a role is too much. And I don't think it's controversial to say the majority of FFXIV players are not into regular day 1 progression and probably pug their content well into the life of an expansion. This means Shadewalker and Smokescreen are relevant, in the grand scheme of the game, for maybe a fraction of the content for a fraction of the playerbase. At the same time, it affects what NIN's toolkit is for every player who rolls it, in that we have this skill, and not a more fun skill instead, that is relevant more often.
The situation you're describing is more akin to a SRPG/CRPG where flexibility and maximizing efficiency is the name of the game, and that's a totally valid, classical approach for MMO design, but that's definitely not the direction FFXIV's heading in.
And this discussion started off as a spinoff of the inevitable pruning they must do if they want to have room to add more skills without crowding our bars. What would you really prune from a class, abilities they use 95% of the time or abilities they use 5% of the time? To add new things, and also keep niche skills, while suppressing binding/rotational flexibility, is describing a completely different game than what FFXIV is. For example, if all the classes were retooled so you don't need to press a button every GCD, yeah, I could see Smoke Screen and Shadewalker being good skills for a game like that, where enmity/aggro really mattered for every pull, like it used to in the days of yore.
But that's probably not happening ever. Enmity/aggro manipulation is a dead design paradigm for a reason (the average player doesn't enjoy it), and I don't see it coming back, nor do I see merit in halfheartedly pushing it on players.