Anything that required(s) stun is usually tied into chain stunning anyways iirc. (t5,levy Ex) Ifrit was the only mechanic where i would break a rotation to stun, but that was prior to being over geared, now you just ignore and burn thru.
Whms chain stunning is more for speeding up Fights and dps, not for dealing with a mechanic. fights that actually requires you to plan ahead is most likely a bosses scripted fight and stun doesn't work. trash mobs and Adds excluded (whm spam gusts in t13).

Pld stun is fine as is, and I never use it nowadays unless I'm doing old content t5 or levyex. On my war, stun is just part of my rotation