After playing through some expansion zones and experienced flying, I have realized how terrible the ground mounts are in comparison. While this was to be expected, it almost seems like SE is trying to make them completely obsolete in future. Give it a couple of weeks and you'll see everyone in sky. There are two main issues!
1. Expansion zones have too many dead-ends for ground mounts. You always have to take long detours to get somewhere. They made these "one way" paths purposely, so people work towards unlocking aether currents. By one way paths, I mean there are many spots where you jump through the height and then there's no way to get back except through a long detour. It wasn't like this in vanilla zones.
So far, this has made questing quite irritating and then once you unlock all aether currents, pretty much all quests are done. I know they probably won't fix these zones, but they should take ground mounts into consideration for future content.
Now onto second issue and this is more important...
2. Where are the mount speeds?! These new zones are massive and it's one of the reasons why flying is so much better because its mount speed is faster. Ground mounts need an upgrade system at this point. I would highly suggest that they introduce a mount speed upgrade questline similar to Relic weapons. For example, start at 100% and then upgrade in small increments like 110%, 120%, etc and then cap at 150% for now.
These faster speeds should also make older zones more bearable since once you unlock flying, going back to older zones feels.. ugh especially Camp Dragondead.
If you guys agree with this suggestion, vote and keep it bumped for devs to see.