It is an issue you seem to take particular exception to, I can't recall anyone else having it.
I do. I encourage you to go back and read some of the big threads here, and see for yourself, that there were others who felt exactly as I do (some argued even more passionately on the matter than even I).
I like agency for my PC it is why I like balanced power levels including point buy stats, broadly balanced class power, even levels for new characters. I am anti fudging, anti "GM story telling" & so on.
That's great. Honestly. But I fail to see what that has to do with our discussion.
I do not find the leader role as it was called actually requires being a "leader" in the sense of bossing around the other players.
Odd statement given the mock-up you just posted with abilities such as "Respected Leader", and abilities that direct the other PCs (attacks and movement). How do you envision such things playing out without you telling them how to think, feel and act?
When 4e came out I was playing City of Heroes which had classes that mirrored 4e roles. Except their defender class was called Tanker & their leader class was called Defender, which is a much better name IMO.
If we leave the baggage of support characters being called leaders in 4e & call them defenders or describe them as support characters or anything that removes any hint of a connection with them removing player agency by forcing other PCs to do things then do you still have a problem?
Is the class' fundamental functionality (I get into this more at the end of this post) tied up with telling the other players how their PCs should think, feel and act in order for it to contribute? Then yes.
I play a lazy warlord in 4e right now I am a used Kank salesman in Darksun based on a character in British TV called Arthur Daley who was a wheeler/dealer that relied on his "Minder" Terry to do all of his fighting (the 80s show was called Minder & I remember it being great 30 years ago).
I grant other characters attacks a fair bit plus tell them to dodge trouble & heal them & let them move around a bit more than usual.
That's marvelous. I love it.
When granting them attacks I have never been accused for removing their free will rather they like to make more attacks to the extent that I spread them around a bit more than is strictly optimal (though this is 4e so we are pretty safe).
4e != 5e. I played a few warlords in 4e as well. My dwarf bravura was probably my favorite. Warlords serve(d) a great role in 4e. But that in no way means they are necessary in 5e.
While I could play a leader as an imperious bossy boots* it would still not remove agency from the players...
Subtle, insidious evils are the worst kinds of evils. Frog in a cooking pot. Et cetera, et cetera, and all that jazz. Just because you aren't overtly usurping control at all times, doesn't mean it doesn't happen in discreet moments or in certain situations. Also, you may not even be aware that some of your fellow players might feel pressure to acquiesce, because as your friends, they want your character to contribute meaningfully. Maybe they don't want to sound like jerks for stepping on what you consider enjoyable. And so they compartmentalize. I know this happens. I've experienced it.
...there would still be the out of game social contract that they get to do what they want to do. I cannot compel either them or their characters in game to actually do anything they do not want to.
And if they all decided to stop receiving your warlord gifts? How much fun would you have with that character if none of them ever accept your various leadership-y benefits (bonus attacks, movement, inspiration, healing)? Exactly. Maybe that's why they do it? So you don't lose your fun. Your choice to play a warlord tells the other players at the table what kind of fun you are seeking. For them to step on it can say as much about them as your choice says about you. People sometimes forget that that's part of the social contract as well. Sometimes people accept contracts with parts they don't necessarily like. Whether for the greater good, or because they get to participate at all. But it happens all the time. I know this happens. I've experienced it.
Of course I like warlords
Awesome. There are great games/editions for that.
I like to play superhero RPGs. There are great games for doing those as well. Doesn't mean 5e is better for trying to handle it either.