No, no it isn't. It is burst 3 (minimum burst 2, for a smart Wizard). Tell me you can reasonably guarantee you will hit no allies but every single enemy with a burst 2 (5x5). You can't.
Not according to the Compendium:
Winged Horde
At-Will Arcane, Implement, Psychic
Standard Action Area burst 1 within 10
Target: Each enemy in burst
Attack: Intelligence vs. Will
Hit: 1d6 psychic damage, and the target cannot take opportunity actions until the end of your next turn.
Level 21: 2d6 psychic damage.
So yeah, if you are going to house rule the area of effect, it will be even better.
And Staff of Ruin+ anything else (Weapon Focus) makes Winged Horde pull ahead. I didn't even have to add any other feats/PPs/EDs or anything (results the same, just happens sooner). Yes my +50 is highly optimized because he he is basically a striker. And? That is basically equivalent to a Sorcs bonus damage. What are they? Oh, yeah, AE strikers.
Still waiting for your mega-list of static modifiers.
There has to be quite a few of them to make it better damage-wise cause the ultimate control is damage, not taking away OAs.
But the bottom line is that not all Wizards have Staff of Ruin. Not all Wizards have Dual Implement. The fact remains that one has to make specific Wizard builds for Winged Horde to be consistently better, just like one has to make specific Wizard builds for Scorching Burst (e.g. White Lotus Riposte) to be consistently better, just like one has to make specific Wizard builds for Thunderwave to be consistently better.
And we never said it was always better. We said "If damage is what you are going for, given the tools available to a Wizard to increase his static mods and enlarge his spells, an enemies only AE will hit more targets, and therefore have higher average damage, by early Paragon. Plus, Winged Horde actually has a controlling element, which wouldn't be a terrible thing to pick up while playing a controller." All of which is undeniably true.
I didn't say that you said it was always better. firesnakearies said that Winged Horde is always better, but you didn't. So, I guess the collective "we" that you are referring to did state that.