I'm not sure if a conversation has been done on this yet but it does seem like a viable playstyle for SMN, the question comes down to if this is how SMN is designed or is this an exploit.

If you notice the SMN abilities are on different timers for their pets, it's not a straight 60 60 60 second recast for one ability but rather at times something like 40 60 60.

What's interesting about this is the following:
Titan and Garuda's basic action is on the first attack line, however Ifrit's Stun attack is also on the first line, the one with a 40 second recast, however you are able to bypass this 40 second recast by Summoning out Ifrit and replacing him with titan or garuda and having them use their ability.

With swift cast and 8 second cast time, it's about 10-12 seconds to regain that 40 second recast ability which could prove to be useful when you also consider taht Ifrit's "basic attack" is on the second line.

For Titan and Garuda their 2nd actions are Mountain Buster 15 seconds and Shockwave 90 seconds.

Now this is where it gets interesting, you can regain Shockwave in 10-20 seconds as well by going back and forth between those two summons, pretty much giving you a nearly instant stun as well as a nearly instant pushback. While it might not seem like a lot, it does add a bit of utility to SMN since in theory they can become a viable stunner during a boss encounter.

Stun Wise they have Ifrit and Titan. Titan's stun is on the same line as contagion and flaming crush so it comes down to whether or not you want to use contagion or not, but at the same time landslide is on a 40 second timer, so you can save a few second on regainin contagion by summoning titan and waiting out the timer and as the timer on it goes off you add the 3 DoTs summon garuda to apply the DoT and then switch out back to ifrit to speed up the recast on Contagion.

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Though again it does come down to if this is legit to do or not, if it is then it does add a whole new dynamic to how one can play SMN where they can actually switch between summons manipulating the timers on recast in order to use their abilities more often, however if this is actually an exploit then I guess ignore this lol.

But overall this is what one should keep in mind with each ability :
Set 1:
Rockbuster=1 second
Windblade=1 second
Crimson Cyclone=40 seconds, Stun

Set 2:
Mountain buster=15 second
Shockwave=90 seconds, pushback
Burning Strike=1 second

Set 3:
Earthen Ward=120 seconds
Aerial Slash=30 seconds
Radiant Shield=60 seconds

Set 4:
Landslide=40 seconds, stun
Contagion=60 seconds
Flaming Crush=60 seconds

I mean yes through this technique you will be burning through more MP using it to summon the avatars more but if this is a legal form of playing with the avatars then it doe give SMN more crowd control as well as give their Energy more use since it can be used to regain the MP lost from summoning the new avatar out.