With regard to 1) the issue for me isn't even rotating exclusivity. I'm level 1080 or so, playing with mostly top 50 guilds or guilds that put in the effort of top-50 guilds so I've had a decent amount of resources come my way.
I have 3 mythics, most recently Gard's Avatar during its exclusive week on PC, the other two were acquired randomly before that. Since then, nothing. No doubles. Not from legendary tasks, nor VIP chests. Nothing. I've cashed in every key, every gem, every guild seal.
I could perhaps rationalize resource hoarding for each monthly mythic week if I felt like I was at least seeing a mythic drop every now and again but for me (and I suspect many others) they are empirically just not dropping. Which is entirely in the nature of RNG, I understand, but the devs have made pretty much everything else in this game accessible to FtP players.
The end result is, I think, a feeling that players have that they won't ever get these cards. Whether that was the devs' intention or not, that's how it's making people feel and they should be aware of that. I found Sirrian's response quite encouraging and I have no doubt that they will eventually do us a solid