First off, a preface. I am making this custom to be able to equal my brother's AT-AT(when and if he gets it) because we do both legal battles and MASSIVE battles. I think the highest we have gone is two thousand points. However we agreed that if he ever got an AT-AT we would do a 5000 point battle with one add-on faction and around 400 immediate reserve at a set round during the game. As it stands now, he will be using his vast Imperial army and his Rebels, while I will be using my almost very-large army of Republic and my New Republic, with GMLS so all my Republic Jedi get Force Renewal. Anyway, he would have this colossal miniand I would not. To make it fair, I am creating a colossal mini to match his, (along with tweaking the AT-AT abilities to make it more playable) So here is a list of Ideas, in no particular order, that I would like honest opinions on. Thanks in advance.

Troop Transport: Characters may end their turn within this character and will move along with this character as it moves.
I did some research on the AT-TE and some of these ideas are based on that research. For instance, the AT-TE could hold up to twenty clone troopers. Although that would be sweet, I think I will make it a little less.

Enclosed Transport:Characters within this Transport cannot be targeted while this character is not Deployed While enclosed in this Transport characters cannot be activated.
Mainly I want to address the not activating part. If with two equally sized armies the transport would be the last character to activate and decides to Deploy allowing those characters enclosed to be able to activate, the other person would still have an equal number of characters to activate. So it's fair-ish.

Deploy/Un-deploy:One Activation: This character cannot move while Deployedbut allies may enter and exit this character. A character cannot exit and enter this character in the same turn.
I do not want this to be abused as a Mobil Attack Fire Base!

Ion Shielding
An AT-TE could not be effected by an EMP blast, because of internal electronic stuff. I'm not a doctor, I don't really know these things.

Taking a Chance Ideas on names? :When this character is defeated while Un-Deployed all characters within are immediately defeated. NO SAVE...BA BA BAM! While Deployed Save of 11

The Rule of One Hailfire Droid Missile? If this character fails a save with a roll of 1, for an effect with taking damage, this character takes X2 damage.
How else do you explain in Episode II where the AT-TE is taken out in one shot? I think it went something like this. "Sir, missile incoming! Save 11" "Roll the d20 Private" "Sir, I rolled a 1!" "Oh #$%@!!!!" BOOM!

More Ideas are incoming, so if you could critique and give your opinion, it would be great help. And don't worry, I have a thick skin.

You should add something to the effect of what the AT-TE was in battlefront 1, where for each trooper inside the AT-TE it gets more cannons to fire! and, like, the back and side cannons could have arcs of fire, and then IT COULD SHOOT BEHIND ITSELF because it could do that in battlefront 1. imo, it could work.

Same round? That means only activating once per inish. Do you mean once every phase?