Certainly an interesting take on skew lists, I just don't think it'll have the stopping power necessary to be honest, as the list maxes out at pow 13/14, so even though it's armour skew, it will struggle against others with a few heavies (against most heavies, it'll they'll be dice-7 even when choir buffed), while most heavies will happily munch through 1-2 Vigilants a turn. That's why most light-spam lists need casters with the "Synergy" spell, or similar to really shine.
It'll also struggle against weaponmaster infantry swarm - Bane Thralls and similar will still rip even ARM21 easily, especially combined with other damage enhancers available to most armies.
The list could definitely be affective if the opponent took a lot of low-power attackers, not expecting the skew, but Jack/Warbeast heavy lists and
WM-Infantry swarm lists are just too common generally to count on that a lot.
I suppose you could combine it with some sort of infantry swarm list yourself, and play list chicken in two-list formats

Give the opponent a hard choice.