It's not a matter of taste. The idea is OBJECTIVELY bad. Say the game has henchmen. My character could pick up a couple of warlords to use solely as "Action Batteries". Say the 20th level wizard picks up on this idea and employs an army of low level warlords. He can now cast all his spells in the first round of combat.
And then there is the fun issue. How is someone going to have fun with a class that the best thing it can do in combat is give their turn away to someone else (at least beastmasters control their pets)?! As I said, it's like paying someone else to play for you.
I have no issues with there being a class called warlord in the game. What I have issue with is giving them abilities that could only be achieved by magic and handwave "it's not magic, honest".
The truth is, the game already has warlords covered thematically: they are called bannerets and battlemasters; and mechanically: in Law clerics. The only thing missing is the name, and I have no objection to that.
I can't believe I'm getting sucked into this again. I was just making a bit of a joke about warlords, since I know that it's not going to happen. But, this? This is just wrong.
What's stopping your character from picking up a couple of Battlemasters to use as "action batteries"? Oh, right, you think that warlord action granting must apply to spell casting... something it never, ever did. But, that's okay, since, you've obviously spent some time actually learning what the 4e warlord could actually do before going on about how it's an "objectively" bad idea.
Of course, the thing is, I can RIGHT NOW play a class that lets me give away my turn - the Battlemaster already exists. So, it's not like the mechanic is a problem. In fact, virtually every warlord mechanic already exists in the game... just not under one class. So, it's not the mechanics that are a problem.
And, the final thing is, what warlord abilities were "magic"? Arguably healing I suppose, but, that ship has already sailed in 5e -we have non-magical healing with the fighter and full overnight healing. Other than that, nothing a warlord did was even remotely magical.
So, let me ask this, what 5e class would let me grant movement to the entire party on my turn, and allow them to make a trip attack during that movement? That's one of those "not really" magic powers that apparently warlords had.
Sure, I can get about 70% of the warlord. I just would actually like the class. No, that's not true. I'd actually like it for WotC to actually have the intestinal fortitude to pose the question to the fandom. If the fandom speaks up and says, nope, we don't want it? Then fine and dandy. I'll accept that. But, right now, it's completely swept under the rug and not even acknowledged. And that's a bit annoying to be honest. Being turned invisible because WotC is too scared of the blowback from edition warriors.