So after I have finished CMs with the majority of my characters (7x 9/9) I decided to get CM with my Druid purely as Guardian. I was wondering if you guys have some information, like BiS gear list, optimal talent & Glyph choices or generally some tips and tricks as a tank. I would greatly appreciate any help that you can provide.
Guardian is pretty easy in Challenge Modes. Keep Savage Defense up for trash packs and you'll be fine. I went 9/9 gold in 4 hours without bothering to farm gear beyond my raid set. Only talents I think are mandatory are Typhoon and Nature's Vigil, everything else can be personal choice.
Honestly I just went with my normal raiding setup didn't optimise anything for CM and I was fine just keep SD up as Trubo said and never be afraid to use SI even on small trash packs
SI glyph might be good to have it up more often for the packs, but not as useful for extended packs. Make sure to abuse the hell out of Ursol's/Typhoon for kiting, it will definitely save your life. Other than that, your rage will obviously be lower, so don't Maul as much, if at all.