This list is focused on weight of fire. 3x AT-RTs with Rotary Blasters and 4x Rebel Troopers with extra troopers and Z-6 troopers, as well as Targeting Scopes. With the Surge->Crit on the AT-RTs and the Targeting Scopes on the Troopers, should be able to put out some decent damage with all of those dice being thrown. No dedicated anti-armor may be an issue. Tell me what you think.

Luke is sorta anti armor. Just roll a bunch of dice and hope for some crits. (Or lock the doors...and hope they don't have blasters)

Overall, not bad. From my games (and this is coming from the imperial side) , I've noticed a single AT-RT with Flamethrower is super effective at clearing out my stormtroopers. You might consider adding one in to mix it up. Also, I'd definitely consider swapping two of those concussion grenades for impact grenades to give you some potent, close range, anti-vehicle firepower. Also for your specific army, I think battle meditation might be a better choice than Jedi mind trick as you'll have ample suppression from your other units, and in case one of your troopers deploys/moves far away you can still give it clutch orders.

Strip down some of the more situational upgrades (grenades, scopes, comms) and you can fit in a whole extra squad with Z-6.

Those upgrades are sure nice, but they're no extra squad.

Guess I should have mentioned this built with my current collection. Split two cores with a buddy then picked up an AT-RT box and 2x T-47 boxes. So limited to 4 Trooper squads and no Impact Grenades at the moment.

10-4 on the availability of minis.

Toying with similar concept except dedicating one squad as an "armor hunter" and countering with an AT-RT with a flame thrower. Specific units with specific uses. Force the Imperial player to account for both. Not necessarily even dedicating the Ion Trooper just the appropriate grenades or both.

Meanwhile, as @Tvayumat said, you do it right and you get an extra squad.

An AT-RT/Flame Thrower in range is a problem. Like, can do just as much as Luke or Vader in melee vs troops. Handful. Getting in range another problem and my thoughts ... all those Z6 create suppression and damage at a decent range.

To be honest I hadn't considered Suppression delivery, I was just going forma many dice with as many re-rolls as possible. Now that you mention it, however, with this setup you could dish out 11 (12 if Luke shoots) suppression a turn.