The sequence with Thunderstorm, Earthbind and Fire Nova can work fairly decently.

However, if you use any of the abilities outside of the sequences then they start to fail. For example, if Thunderstorm is on cooldown for #1, then you get Nothing + Earthbind + Fire Nova + Null. Now the sequences are out of whack.

You can include a reset in the sequences, either reset=mod:alt or something like that, or I usually find the longest recast spell (in this case Thunderstorm is 45 seconds) so go with something like:

/castsequence [nomod] reset=45 Thunderstorm,, Fire Nova, Earthbind Totem

At least this way, 45 seconds after you've used it, they reset to the default order.

It is still spammable if you want.
And it gives them a push back, snare (short duration root) and AoE (with short stun) to deal with.