The trouble though is that sometimes including stuff diminishes the things you like.
The Warlord, for instance, by including him, you're are saying the Fighter now has a very limited role, rather than being the leader of men he was portrayed as in D&D/1e (where he eventually got to rule over a castle with followers), he's just a got that never talks and hits things with a sword (or axe).
Beyond that, it reduces the role of role-playing. Players should be leaders, not their class.
Why does a campaign have to include him?
Beyond that, in 3e there was a divide between a soldier and a leader. Same with 4e.
Indeed, the only thing that marked a leader-type fighter in 1e was the automatic followers at what, 9th level. But then, that was true of most classes, as I recall.