1) Since the launch of HW i think (I still remember needing to level both Conjurer and Arcanist for Scholar and whitemage). Though i took a long break until the middle of Stormblood, around the time Tsukuyomi released.

2) Im exclusively a KB/Mouse user. tried controller once, but i just couldnt get the hang of it.

3) Id say its about right. Though i do find myself looking for more challenges like solo healing content or doing mentor roulette with 7 sprouts, to get that extra kick out of it.

4) Like i said: Endgame content and Mentoring. I guess i just like, if things go sideways.

5) I maxed all of them, and 2/3 are BiS gear. My prefered healer changes with content and mood, but generally id say 1st: AST, 2nd WHM, 3rd SCH.