Just because the Egi's are of different elements doesn't mean that they need to *do* elemental damage. Its just flavour for the class, it makes sense based on the lore of the game.There are several ideas for elemental wheels for different egis - but after all there are no elemental modifiers in game anymore whats sad - on the other hand it would cause even more balancing problems than we already have.
I'll be honest, I've no idea what Shockwave is aside from that Adobe thing. I'll try to be more clear though so you understand what I mean. Starting with the Summoner, using Ruin I would do just that, deal Ruin I's damage and that's it. Then, as the next GCD move you would use an Ifrit move. If they use the bare minimum that I'd want of 6 moves, it would be one of these. Specifically, perhaps it could branch off from Ruin I into either a single target high potency move or an AoE move. Then the Summoner's Ruin II would be enhanced in damage, where before it does X potency it would now do X+50 because you're comboing it off of Ifrit's move and stuff. Perhaps you could even make bio or miasma also like this. This would continue, going back and forth between Summoner and Egi, until the combo ends. Just like how a Dragoon, Monk, Samurai, etc do their combos, it would be much like this. But the combo for the Egi could change depending on which one it is. Maybe Shiva would have more AoE combos to use than single target, or one could have a DoT, the possibilities are only limited to the mind of the creator in that respect. So, as far as I know that would be sort of like micro managing your Egi? You're telling it what moves to use as if it were an extension of yourself, which it kinda is I think? Not sure, been ages since I did the first 50 SMN quests. As for the constant rotation, there's nothing wrong with a that if it's fun and diverse? Most of the classes in the game have very specific rotations and combos, to the point where there is an absolute perfect and desired combo to use mathematically, but these classes are still lots of fun and played..So this would looks like Bahamuts Shockwave hm? I personally don't think its a good idea taking this mechanic to all egis in general - don't we want to be more flexible and effective in micromanaging our pets? this would cause the opposite they would follow an even more constant rotation if you give them a chaining system... but well thats just my personal opinion. ^^