Colisseum - Working as intended?

Yes active vs passive evading or evasion due to buffs, character abilities or leadership abilities/team synergy. 

I don't think, personally, that when you apply a debuff forcing the enemy to miss his next attack, that it should towards them evading the attack and not simply the enemy missing the attack. 

Inherent dodge chance (RJT, Hondo etc), Foresight buff etc I completely agree with and understand - but when you apply a debuff forcing the enemy to miss an attack, that is not evading in my book ^^

I don't know if I can properly put it down on paper - if you are older like myself and you played WoW Classic; the rogue class has the evasion ability and when he dodges a warrior that triggers the Overpower proc, an ability especially designed for the dodgy classes. 

I know the games aren't at all similar but imagine if the warrior could just proc the ability at any given moment, when the rogue dodges him, when he himself misses an attack, when a bird flies close by his head. 

This mechanic for the AT-ST triggers automatically when you have Forsight, (possibly damage immunity too?), when you dodge inherently but is also designed in such a manner that if your opponent stabs you in the eye and you try to hit him and miss, it also procs 🤷🏽‍♂️ that is not good design, especially in an event where you are severely limited in what characters you can use and have no way around it except skipping an ability which is not really feasible since the Overall kit of the AT-ST is designed to demllish you:

1. Basic attack inflicts debuffs, if you have DoTs when he uses the attack he attacks again
2. AoE ability that causes debuffs you can't resist and DoTs on the main target and if he already had certain debuffs remove turn Meter from him 
3. AoE ability number two, causes debuffs and if you have DoTs get blinded and some more debuffs are applied 
4. Then you have bloodthirsty crew ability and guess what if he damages you when you have debuffs, thats 25% offense stacking until the end of battle and if you god forbid try to evade, resist or prevent any of these DoTs he gets turn meter, at the same time as the fight progresses, he just gets stronger and takes less damage

This is my issue with this and the "if he doesn't hit you that counts as an evade" - his kit is designed to cause debuffs and capitalize on those debuffs, ergo, you would want to try and prevent that in a calculated fashion since he also has turn meter train in his kit if you do not accept the debuffs and the stacking offense. Damned if you do, Damned if you don't 🤷🏽‍♂️