On the subject of getting angels more involved, I'm playing one. The MC has done a great job so far. Her first love letter to me gave me a choice of things I was getting work from, and I ended up picking one that went places: a pernicious, communicable, and eventually fatal disease-causing mould, which went on to spawn a cult which has raised a considerable amount of shit in the game. And then there was getting attacked in my surgery and the meds used for treating the mould stolen, which resulted in a tense subplot where we got them back (and the thief turned out to be the hardholder's son, which spawned more drama), and then the MC felt bad about having me attacked in my surgery by a big scary woman with a severe communicable disease and brought a biker gang of potential romantic interests (and subplots of their own, like being able to recruit the gang against enemy mutants, and having to deal with the hardholder who wants to run them out, and so on) into town, and yada yada.
Also, angels have wicked Sharp. I highly recommend using it. Having Sharp+3 (after an improvement, admittedly) is like being a goddamn mind-reader: you excel at seeing through people (and situations), and you should damn well make sure everyone knows it. I also picked the stat array with Hot+1, which helps for following through when I read someone for their buttons.
So I guess where I'm going with this is, you need to consider both what angels as a class do (they cure the sick and heal the injured--a disease or battle that calls for a doctor to save the day will put attention on them), and their individual motives, as you would for anyone. You could try asking the angel's player what the character's goals and desires are, then act on that information. That, and cater to their great Sharp; throw situations at the PCs where NPCs around them aren't wearing their motives on their sleeves or into uncertain situations with dangers that are hidden and not right out on the table.