Everybody loves a vowel progression puzzle! Here, we have H_LL working through each vowel. I'd say they hit on three of the five: HALLOFFAME, HILLSTREETBLUES, and HULLABALOO are all well known and acceptable phrases. HELLOHOWAREYOU is fine; it just seems a bit strung together to fit in the grid. I mean, would we accept "hey, dude, how's it hanging" as a phrase? Maybe I'm being nitpicky.
On the other hand, HOLLYWOODACTOR is just too blah. I wanted it to be "Hollywood star", but that didn't fit. I feel sure this could have worked just a bit more tightly with a little jiggering.
The grid has two long down answers that span three theme answers. ALLFEMALE is accurate, but doesn't feel organic. RULEOFLAW is very good.
Otherwise, the fill is reasonably good. I liked that both current ASTRO and retro OILER make it in. SIR, OFART, and the most peculiar partial I've seen in a while, ACAB, are not great. 1A: Name of five Norwegian kings (OLAV) gets a C-, because I had to guess whether it was going to be a V or an F at the end. In fact, Google likes the F better.