Ziplines and Sliding are the worst features to be added into the game, they seem like nice mechanics, but they are implemented poorly into the current game. The maps being updated to fit these new mechanics is a poor design choice, these maps were not made with these mechanics in mind, and result in poor gameplay.
Poor implementation of Sliding can be seen in maps like Poisonous Chasm, after the section of the first button, and mid-platform in maps like Wild Savannah seems very unnecessary. These mostly make the gameplay experience sluggish rather than more interesting or fun.
Ziplines also suffer similar problems, the one in Snowy Peaks is one of the worst implementations of it, as it only makes simple maps overly complicated. Another example of this is seen with Fallen, where the zipline takes you to the actual beginning of the map after 5 seconds or so of riding it.
A good solution would be to revert the current maps to pre-update and instead opt to make new maps that are intended with these features in mind. Fixing up these mechanics may be needed as well, making sliding faster, and switching between ziplines seem like cool additions.
Both of these mechanics are pretty decent, they just aren’t meant for these maps, and need a bit of updating to make more enjoyable. At the given moment, they just feel like random things shoved into fully working maps. I personally enjoyed taking as little time to finish a map, taking as many shortcuts available, and these new mechanics take away a lot of that and limit the freedom you previously had in these maps.
EDIT: This was simply my take on the Agility Update. I saw that FE2 has been updated with changes removing various sliding that hindered gameplay and tweaked a bit of the mechanics to improve how they fit in the map. However, my opinion hasn’t changed much. Sliding and Ziplines are added in a very unnecessary format and don’t really work well since the maps weren’t designed with the mechanics in mind to begin with.