Even without the Perfect, just having blockers is enough. The Angel is a 4-turn clock on its own and being able to chump guys in order to protect her will pretty much guarantee a win. Given you should be able to crank out creature after creature, you should be able to block them just fine unless they happen to draw enough remove to kill all your blockers at once and alpha strike to kill her, but even then that's rare.

However, I feel in almost all circumstances getting Progenitus is a better play. Empyrial Archangel is pretty much only better if you're very low on life and need to stay out of burn range. Their creatures are usually much larger than ours because of removal hitting the lords, so within a couple turns they can take down the angel anyway. I'm much more comfortable playing Progenitus and simply racing them, which has worked a good amount of the time. Progenitus itself time walks them as they aren't going to throw creatures in front of it, but they can take down the angel if they have a couple creatures and a burn spell. Instead, putting them on a 2-turn clock is a bit stronger because odds are you'll be able to dump out 1-2 more creatures the following turn to block, then win the game the turn after.