Very nice. Here's my thoughts:
Name "Paladin Cavalier" = cool. My first proper Paladin was one of these for a while, until we agreed the powers were too much and dropped the cavalier part.
Str & Cha, at last how it should be. Dropping wis cures the mechanical MAD, but lack of wisdom (as emphasized in virtue of valor text) is one source by which a Paladin Cavalier loses their virtue & falls from grace.
Divine defender. Despite their appearance, the paladin's powers & theme are all attached to their higher calling. The martial is there, in proficiencies. but it's not enough to tip any balance. I can buy this.
The emphasis on a Paladin's virtue as the source of their divine backing is well done. A Paladin was always marked by their attempts to live by their lofty ideals, and this codifies it. With a list of virtues we now have a spread of Paladin types. The presence of vices & blackguards pays homage to paladins falling from grace and emphasise how being virtuous is a constant journey.
Overall good flavour text.
Paladins now have martial missile training - bows! Dex... Well with the MAD under control you could bump dex a bit on the way to say shield spec & heavy weapon mastery. Then again wis for skills, and say, wisdom.
Skills have been expanded by athletics (key stat too) and religion is now optional. We've got a couple of int & wis skills here, so a pal/cav can be pretty well rounded if you choose.
No write-up for the virtue of justice... :-(
Ah well, we've got an easy to remember defender aura that doesn't need tokens, and a whole lot of powers without descriptions. No doubt the smite adds a +(W) per enc, righteous radiance puts a smack on a foe within the defender aura, and the righteous shield protects a nearby ally from harm. A bit of healing at lvl2 and a mount at lvl4. I think we've ticked all the boxes?
Nup, we've also got ye olde spell casting perhaps at level 5 (fingers crossed).
Virtues give a base benefit, decide the 2nd at-will (methinks valiant strike can be interchanged with holy strike etc?), and has an alignment prereq. Going back on what I said, I think the dailies/utilities may be virtue based, although perhaps still spell-like. Otherwise the strong virtue start will weaken through level progression.
Alignment. Good to see it's back in a codified way. Valor & sacrifice contrast quite well. Valor has a more open prereq and indeed, to get the strongest value from the at-will you want an ally to be bloodied. "Vengeful" is a dicy term too. The LG only sacrifice power has better effect when an ally is bloodied too, although there's not quite such a desire to see them so.
Overall I'm pretty keen to get my hands on this class when it comes out.