I’m one of the not-very-young-anymore posters (late 30s) and [name]Phyllis[/name] was an “old lady” name even when I was a kid. Not a mom name, but when I was little, maybe old was younger than I think it is now… er… Anyway, I’d lump it in with names like [name]Louise[/name], actually. We had a neighbor named [name]Louise[/name] when I was a kid that makes me feel like that is around the same age as a [name]Phyllis[/name], and yet we are embracing [name]Louise[/name] now. I don’t see why not [name]Phyllis[/name].
At least 10 years ago if not a few more, I worked one summer with a young [name]Phyllis[/name] in her 20s. She was so cool. I never worked closely enough in her dept. to ask her about her name, nor have I typically been comfortable enough to do so. I kind of like that pre-hipster don’t-care-about-trends name that she had, working alongside [name]Nicoles[/name] and [name]Jens[/name] and Julies and Jessicas and Stephanies. I really think [name]Phyllis[/name] works and is not forever unusable. It might be too soon for your parents to embrace it, and obviously some of your peers who would love a little [name]Hazel[/name] or [name]Helen[/name] or [name]Louise[/name] just can’t dig [name]Phyllis[/name], but I feel like it should be. It’s a pretty little name. That said, I also like [name]Felicity[/name], so I really think [name]Phyllis[/name] has that sound appeal already in the atmosphere. I don’t really like [name]Felicia[/name], and not sure how people can bypass [name]Phyllis[/name] for, say, [name]Philippa[/name]… [name]Pippa[/name] might be cute, but I can’t figure out [name]Philippa[/name], it just sounds so awkward with that PAH sound, although I do like [name]Philip[/name]. I would definitely consider [name]Phyllis[/name]. It looks so organic, means foliage in Greek. It has similarities to other names that mean happiness, luck, and love, as well as sharing some similarities with names that are being revived, and names that are currently or recently popular (from [name]Felicity[/name] to [name]Melissa[/name], anything with an ISS), meanings that are significant and good and healthy, leafy and natural, that are appealing deep down. As we know, some names may sound ok, but have a really unsettling and offputting meaning to people who care about the whole package.
Side note: I am also and have been for a while, fond of [name]Doris[/name], which is another name people consider unrevivable. Back there on Appellation Mountain, the commenters consider [name]Doris[/name] not yet old enough to be appealing. I say who cares… sometimes 
Like I said, I met a very nice and cool (when I say cool, I mean easygoing and funny and not at all dowdy or even introverted, not ultra-hip or dangerous to know!) young [name]Phyllis[/name]. I don’t know if her childhood with that name in this day and age was horrible, but she carried it well. Someone has to be the first. If you like a name a whole lot, it might be a decade or maybe more before [name]Phyllis[/name] is at least “hipster” cool, and by then if you still want to and are able to use it, it might seem a little like following the trend, letting others decide when its time has come.
I am in favor of this name, although I can understand a lot of people discouraging it on some ideal standard - while adoring other names I think arbitrarily or because others have convinced them. I bring up [name]Hazel[/name] again - it’s a mystery to me how [name]Hazel[/name] gets stamped as ok, but like, no celebrity has given permission to use [name]Phyllis[/name], so it’s still too far for some people to go.