Why is the game adding this "complexity"?
Because other people keep asking for clarifications.
Don't blame Jeremy for answering these people's questions... blame those other people who staunchly refused to do what WotC told them to do when it came to 5E... making rulings not rules.
If those people had done that... and NOT tried to get Jeremy to reveal what they meant by the way they wrote their rules... we wouldn't have received any Sage Advice and we wouldn't be having this conversation in the first place.
And on top of that... you can also go ahead and blame yourselves for your own aggravation, because you *also* are disregarding 5E's "rulings not rules" mantra by reading these articles and then believing you actually have to USE all this Sage Advice in the first place.
You don't. You never had to. 5E told all of us to make our own rulings if there was any question or concern. So do that! After all... if you just forced yourself to never read these articles (or even just *pretended* that you never read these articles), you'd never have known this so-called "complexity" now existed, and thus you would have made your own ruling in whatever format you chose to do and wouldn't get all upset about it now.
Hell, that's what I do. I personally think the Assassin not being able to use his assassination ability in the surprise round if his initiative roll is later than the person he was assassinating (who didn't even know the attack was coming but yet somehow has a Spider Sense that allows him to act faster and no longer be surprised by it) is a fundamentally flawed idea. So I don't give a rat's ass what Sage Advice says... I made my own ruling on it.
And I do that for everything. Because the entire book is Ruled As Intended. MY intention. What I think the rules should be. What makes sense to ME. And screw everybody else and what they believe.