I like the build, i would move Nashor's Tooth before Hextech Gunblade, better mana regen, cooldown, AP will give you the better support build you are looking for then the lifesteal, and your swing speed is to low to really reap the life steal benefits at that time in your build.

How do you think Kayle's playing style will differ after this upcoming patch hits?

i like it, though i found that building shred, (malady and black cleaver), couples with your passive very nicely, and over time you can become an insane asset to your team, while still getting ap (nashors tooth, lich bane, rabadons) to heal and slow the enemy a lot. the guide is very bland right now so i have you at a +-0

even though your trying to make a support build, 1 point in righteous fury should still be taken early.

why? for 40 mana you have amazing harass capabilities and your not useless in lane

kayle cannot babysit like soraka. she has to be agressive like taric/lulu/janna/etc

this is why you need righteous fury early