Mandelic Acid Serum? Still working on it!

You guys, I haven’t be able to make my ideal Mandelic Acid Serum yet. I’ve continued to work on the basic supporting structure of the serum, but something’s missing. Version 8 is closest to what I’m looking for but it’s still not quite there. sigh
In the versions I’ve made so far, if I like the consistency, I don’t like how it feels. If I like how it feels, I don’t like the consistency. Or, the preservative is giving it a loud smell that requires a fragrance. Or, it’s a tad tacky. Or, it’s simply not soft enough.
So, I’ve decided to turn it over the community. What do you guys think would really set this formula off and finally provide the umph I’m looking for?
Remember I’m working on the chassis, or the basic structure first. Then I can load it up with extracts and extras.
Here’s what I have so far (version 8):