Starting without equipment

[Mad Hamish]

This, however is something I don't get. Are you refuting that every class has powers that don't target AC?

I'm not up with all the classes powers. Rangers have very few non-ac targeting powers,
The earliest one seems to be the errata'd Shadow Wasp Strike which is level 3 iirc. Then there are a few at level 7, most of which are limited to 1 build or another.
So at best you have 2 of them in heroic and you're unlikely to pick them both up.
(I'm not counting secondary attacks on a beast power)

A rogue will commonly have the At Will that targets reflex but I'm not sure you can expect a weapon user to have many options other than AC, certainly at low levels.

and there's still the issue that a rogue can't use his powers with just any weapon.
Sure the GM can give him a chance to get an appropriate weapon early (pick-pocket the guard captain to steal his dagger in the first round of the fight for instance), or allow them to use it barehanded but without a GM ruling if all that's available are improvised clubs or battle axes you can be cut off from rogue powers. A GM can work around it but it's something they have ot think of and do.

Nor would I guarantee that a Fighter will have one, there are a lot of good at-wills around for a fighter.
(The fighter I'm going to be playing in my next campaign has Weapon Master's Strike and Footwork Lure being a Greatspear user)
While knocking things prone can be handy it's somewhat party dependent (much nicer with a rogue and a barbarian as strikers rather than an Archer Ranger and a typical warlock for instance) and in the cases of soldiers and brutes fort tends to be up around the AC value anyway.

Avengers have 1 at will that targets non-AC and it's a ranged implement power that doesn't have their oath on the effect so it's questionable how often it'd be picked.

 

[Saeviomagy]

This, however is something I don't get. Are you refuting that every class has powers that don't target AC? Or are you refuting that a weapon using class using those powers unarmed will be in an identical situation as an implement using class using its powers unarmed?

A rogue who is unarmed, and who doesn't have the rules changed for him can only use his utility powers from his class. Not a single rogue attack power doesn't require a weapon from a specific list.

So, yes, I'm refuting that. The rogue has powers that target non-ac defenses, however when he is unarmed, or armed with improvised weapons, he cannot use them.