According to WoWHead the Fluorescent Green Mechanostrider mount has a 1.67% drop rate which is very low considering this is a seasonal game and it’s a raid drop (so you have to compete against 9 more players and hope the master looter won’t ninja loot it).
I’m not saying it should be a 100% drop but I think it should have at least a 10-20% drop rate.
It’s not meant to be easily accessible. Even with the low drop chance, I’ve still seen plenty of them roaming around. A vanity item is just that, a vanity.
Disagree, not everyone needs to get rare mounts, and as you said yourself, this is a seasonal mode. This is all getting punted to some dying server in a year and getting it won’t transfer.
In the non-seasonal classic you had (and have) time to farm the ZG mounts until Cata pre-patch, meanwhile we have only less than a year to get the Mechanostrider. And this is the first time that this mount is available for players.