By all means, those who prefer battlemaster over champion, you're more than welcome to and have fun with that. I currently play a champion and a battlemaster in two separate games, champion level 6 and battlemaster level 11, so I speak from experience.
Yes, its true, with the champion in combat i approach and hit, sometimes separating my moves and hits amongst different enemies. However, I roleplay this to my liking and imagine the combat as a vivid, real time event and that makes it fun. Also, I don't mind a class that does something really well, even if its only one thing, with the champion being, hitting




really hard.
I haven't had the chance to give him great weapon master, sentinel, and get the remarkable athlete yet, so I'll not speak to that, but they theoretically will turn the champion from good to great.
The battlemaster, however, uses a halberd and has heavy armor master, polearm master, sentinel, and savage attacker with 20 strength. He has 5 SD that are D10s. Yes I can nova damage really well, but in that campaign the DM doesn't let us short rest until AT LEAST 4 to 5 encounters, so honestly, being a battlemaster isn't that great. I either have to hoard my SD and therefore that renders me just a fighter with a halberd, or I have to blow my load on a difficult encounter and then I have no SD until rest and, again, I'm just a fighter with a halberd.
My champion, however, laughs in the face of no rests. While everyone else is whining about getting back their rages, smites, and spells, the champion is ready to run another marathon and is wondering what all the whining is about. This, on top of doing lots of roleplay outside of combat since he's a mercenary captain of our unit, and hitting like a truck in combat. I can't count how many times our DM just sighed in resignation when I chopped down one of his big bads with 2 crits, and only 2 cuz i only have one extra attack. Once I get GWM, sentinel, and more attacks, it'll get only crazier.