Ap Ez

[Duronos]

There's the fact that Shaco (a) has another part of his kit that is at least a safety measure (his ult) and (b) not a very common pick these days at higher levels. Using his E offensively doesn't make it not viable, but it does make it less safe than AD Ezreal. Also, Shaco is an assassin. He has the damage to easily knock someone out instantly, even 1v5. If you do that as Ezreal, you will get slaughtered.

AP Ez has it's place, just not as much as AD Ez. The fact that you're saying Shaco also has another tool to escape, dodge, etc. means nothing to me because Shaco is better than most champions at that. I was just pointing out that a free flash can be used offensively or defensively.

[Duilliath]

Yes, but generally speaking, as a ranged squishy, it's a pretty gorram stupid idea to use it offensively because it puts you in A Bad Spot^tm