Concept build help

Well Domis don't get the Earth APP, because too many powers were already in Earth Assault, so thats two options gone

Overall I'd go with Earth/Fire/Ice or Fire/Earth/Ice.

The difference is Earth/Fire is more ranged based and a total beast (Quicksand + Sleet + Ice Storm). Earth has tonnes of AOE control, Fire is brilliant at burning things to the ground. For this build I'd be inclined towards Ice Storm, Sleet and probably Hibernate (because you have so many Pseudopets and an incredibly tough pet you can do what I used to do with my Illusion/Stormie, dump a load of patches of doom / pseudopets down and if things get hairy camp out in Hibernate to heal and regain End while your patches & pets do their thing). Fire Assault does have 2 melee moves (well 3 if you also count Consume), one single target and one PBAOE but both are Damage Over Time which is a slight annoyance (you can still take them, I have, but they aren't as good as Earth Assaults Big Lumps of Damage).

Fire/Earth is far more melee based with less control from the primary but more damage. If you want to play a sort of Domi-blapper go with that. You'll die a lot more probably but you'll live in Interesting Times. For this I'd be inclined more towards Sleet, Ice Armour, Ice Storm and maybe Hoarfrost over Hibernate since you don't have Stoney, who can tank for you, and a 30% heal and +hp might be more useful to a meleer. Earth Assault has the best melee attacks available to Domis but the first PBAOE, Tremor is underwhelming (the animation is slooooow and the damage is crap, but the knockdown might be useful to a Fire Domi).

My main issue with Earth/ice/fire and Ice/Earth/Fire is primarily that the Power Boost from the secondary doesn't play particularly well with Earth Control or Ice Control. Ice/Earth would also be a pain in terms of End costs (as is Fire/Earth in fairness but it does lots and lots of damage). Ice/Earth is also very dependent on knockdown, which can be a pain on teams with other controllers on it (Planties will drive you insane as they cannot help a lot of the -knockdown immobs they produce).

I've never been able to get into Ice Assault, attacks do mediocre damage (but quickly, the animations are nice and fast on it) but the AOE is actually pretty good on it and comes very early. My main problem with it is that it doesn't really know what to do with itself, it lacks focus and doesn't excel in any one area, unlike say Fire, Earth, Thorns or Energy Assault (I've the same issue with Psi Assault, there's a lot of to-ing and fro-ing in and out of melee, especially before level 38 when you finally get your PBAOE, which is admittedly excellent).

I'd say Earth/Ice/Fire for fantastic lockdown and graphics goodness or Fire/Earth/Ice for great damage both ST and PbAoE with good controls.

Can't speak for Ice/ as I've never played the set to a decent level but I'm sure someone will show up and speak for it.