I feel moving Mudras to the GCD was a good change. However, I think it could have been done in a way that let the NIN retain its previous APM.

A brief reminder: GCDs have ping-compensation. oGCDs do not. Every oGCD will claim twice your ping (there and back, so to speak) of uptime in addition to the baseline 0.6 seconds of animation lock, with the exception of mudras, which already may have been a unique hybrid at 0.5 seconds base and seemingly had some ping-compensation.

Moving the mudras to the GCD guarantees up to 250 ms of ping-compensation. That's good. Just by categorizing them in the same way as other weaponskills we apparently already benefit accordingly. But...

Why then add the "Conversely, execution of weaponskills triggers the cooldown of this action" clause? We know from HW-era Empyreal Arrow that skills which trigger the global cooldown or any part of it can offer ping-compensation as per any other GCD; they do not necessarily also have to be affected by the global recast timer.

Essentially, it seems like we could have had the ping-compensation without actually forcing downtime between the previous weaponskill and the mudra cast, so... why slow the combat down unnecessarily? Did they just feel that Ninja wouldn't appeal to players who don't currently play Ninjutsu casts gave a minimum of some 500 potency and needed to make it cost more uptime accordingly? And why the 1.5 seconds on Ninjutsu? We can only benefit from the ping compensation of the first half-second. Why then slow it down? Just to give room for an immediate Trick Attack every time despite that we are already used to using Suiton up to 20 seconds in advance of Trick Attack?

We weren't limited to just Slow or Ping. We easily could have had both ping-compensation and almost wholly kept our old speed. So why the sudden and unnecessary change to the playstyle?