OK, I get it. Some people have to deal with players who will argue with everything they can any time they think it will provide them with additional advantage, and it clearly disrupts their games. That, to me, makes it a plyer issue, and I don't know why people are OK in groups like that, but clearly it's a thing some people are willing to endure.
I don't blame the rules, because in my experience I can use those vague, or open-ended rules, or however you want to describe them, and my players don't become disruptive.
You're clearly adamant it is the rules, not the players, and I'm not going to change your mind, so I guess I will leave it at that.
Again, it's not as bad as you're painting it. It's not that the players are arguing all the time, every time. No one is being unreasonable. That's the thing, no one has to be unreasonable here because, as you say, the rules are open ended. Which means that the players are going to gravitate towards trying to do stuff outside of the box. Not every time. Of course not. Just often enough that it becomes a thing the DM has to deal with.
And, it's not like it's just one spell. It's the fifty or so spells that are in the PHB. So, you spend a couple of years hammering off the rough edges with your group. Great. But, then Dave moves away and Jeff gets a job, so, now you have two new players at your table and you get to start having the same conversations all over again. Then, the year after that, another splatbook drops, dropping another dozen or so vaguely written spell effects onto the group and you spend time every session or two hammering the rough edges off those books. Then, six months later, Peter gets a new job and you're looking for another player which means you get to have the same conversation about the fifty PHB spells plus the dozen splatbook spells all over again. By now, you've finished that campaign, whatever it was, and you're starting up a new one. But two of your players have moved on and now the five people sitting at your table are completely different thant the five you had at the beginning.
Which means you get to hammer the rough edges off those vaguely worded spell yet again.
It's just so exhausting. Because it never, ever ends. It just keeps going around and around, not because anyone is unreasonable, but because while you had that conversation with Players A through E, now your group consists of A, C , and G, H and I. And those three new players haven't had those conversations with you yet.
It's not a player problem. It's a problem with the mechanics. And it is so easy to resolve. The new Command spell is exactly how you resolve this. You tighten up the language a little bit. Not a lot. Just enough to cover 90% of the stuff that the spell was being used for anyway and shave off that 10% that was causing the headaches. Because, again, playing silly buggers with the vaguely defined effects of spells isn't creative. Using a Command spell to lure the troll into that carefully crafted kill box after the party has hammered out strong tactics and plans? THAT'S creativity.