I think the problem stems from people thinking that just because it's a Charmed reboot that it IS Charmed. Mel is NOT Piper. She's not supposed to be. The only things they have in common is that they're powerful women who have the ability to freeze time. Maggie is NOT Phoebe. Just because Phoebe wasn't into social cliques the way Maggie is doesn't mean Maggie is a bad Phoebe. And Macy isn't suppose to represent Pru, other than being telekinetic. It's not supposed to be a copy of Charmed, but a different take on it with the same theme in the same universe.
Now don't get me wrong, the writing could use some work. It's not the best show ever, but for what it is and what it's not - I think it's fine. I like the aesthetics, I like the music, and the characters are interesting enough to keep me watching. Charmed was one of my favorite shows and I'm glad to be able to watch something in the same universe, even if it's very different.