1st I gotta ask, what relevance does using a controller have to whether you play in 1st or 3rd person? I totally don't get that comment.
When playing in 3rd person, using WASD on a keyboard to control a character's movements often feels clunkier than using anolog sticks on a controller. Similarly, when playing in 1st person, using anolog sticks to aim precisely often feels more awkward than using a mouse.
It's no surprise then that a lot of people who favour 3rd person tend to use controllers, while a lot of people who favour 1st person tend to use a mouse & keyboard.
As posted above, I think as a general rule, third-person games (and sidescrolling games) are better suited to a controller, while first-person games (and top down / isometric games) are much more suited to a mouse & keyboard. So action-adventure games, fighting games, sports games, platformers, and racing games tend to be better suited to a controller... while first-person shooters, RPGs, strategy games, and point & click adventure games tend to be better suited to a mouse & keyboard.
I'm sure some people who swear by either a controller or mouse & keyboard will disagree and try and argue that their preferred device is best for all genres... but whatever.
