Mounts - take inspiration from GW2, categorize mounts and let each one have its own set of perks, the mount equipment system is bad.
A few perks could be, gliding, sprint, charge (or a bonus dismount attack), harvest nodes/extra nodes, wall walking, short flight (similar to the fatigue bar when swimming - its a compromise so you can get rid of infinite flight but we can still fly at expansion launch at max level), high jump, long jump, barrier destruction to break obstacles, maybe even an environment bonus for when an appropriate mount is used in an appropriate area. inate mount bonuses like vendors can prevent categorization in this system.
An xp bar with talent system per mount could be great for this.
Pets - the “right” way to do pet battle wq now is with 3x level 1 pets that double counter. The more you level up pets the worse this system feels, this should be addressed. It would be nice to have a world buff based on which pet is currently following you, loot for you, harvest for you, damage bonus (or maybe player power should not be a part of this and only player convinence), more gold/meat/anima drop, move speed out of combar etc some kind of noncombat pet bonus per pet would be a great supplementary system.
Bodyguards - this was a great feature of WOD, I loved it… it was kinda ok in Nazjatar, would love to have more lore presented through doing this… its probably the best way to introduce a new character, have them adventure with us for a while… similar to how crpgs handle characters, we could talk to these guys over time and learn more/bond with them.
Flight master whistle… bring it back. Simple.