Girdeux: Standard mode is not so bad, and the game is designed around it, especially modes with objectives like Sabotage or Headquarters. That's the problem, people want a cheap dopamine fix with 64 players HC TDM spamming LMGs and grenades on a single map over and over, like Crossfire or Killhouse.
Hardcore simply isn't balanced, it makes some weapons a lot worse, some a lot more overpowered. LMGs are meant for support and suppressing fire, but that only works for THAT purpose in normal mode. Shotguns are deadly in short range and damage the opponent faster than even an SMG so usually in a close encounter the shotgun wins, but not in HC. In fact, the SMG will get 4, even 5 kills on a single magazine.
There's many annoyances here and there, and HC has its place, but its definitely not as balanced.
Everything still works almost as well in hardcore, with the exception of shotguns, depending on the map (though, it always depended on the map for that kind). As someone who had no preference when it came to weapons, I generally did really well using all of them.
As for modes: Back in the day I played on a server which was mixed hardcore, aka the server changed maps and modes (too, I believe). I know I played TDM, Domination, S&D and Headquarters, maybe Hardpoint. Was a lot of fun. Too bad they messed up the sequel of the game. And the death of dedicated servers basically made me stop playing FPS games. Only one I did after Call of Duty 4 was PlanetSide 2.