About movement tools

Is there any good reason why Aetherial Shift and Icarus are 60 seconds and 45 seconds instead of 30?

All the DPS and Tanks either have short CDs on their movement tools or charge on them if they're over 20-30 seconds.
They are used purely for movement and the "they're casters" excuse doesn't work because BLM, PCT and RDM all have short CDs or multiple charges on their movement tools and SMN has instant casts.

Healers are already bad enough to play so I don't get why this is a thing, there shouldn't be a healer tax on movement.
Hell AST barely has a movement tool and SCH arguably has the best in Ruin 2.