So I took out my RTW leggings to compare and they all had waistbands that were 10-12 cm wider than the Coras, while still being about the same size around the legs. In the end it took three tries to get a well fitting pair and I ended up having to grade up several sizes at the upper hip to get the waistband to fit.
A couple of people chimed in on Instagram saying that they had the same waist issue. So I emailed Jalie and got a very thorough and helpful reply. Yes the waist is supposed to be this small, and they said that they hadn’t done a pattern test run on someone with my body type (smaller waist/fuller upper hip) which could explain why this issue never came up. So their (and my) suggestion is to check the measurements and do the appropriate alteration if you have a round stomach. Jalie recommends this tutorial for changing the pattern. They also suggest testing omitting the elastic since that hugs the body harder than just fabric.
[ETA: I got a great comment pointing out that Jalie’s original target customers are athletes, which tends to have muscular legs and smaller waists. That explains why their drafts might not always fit a more mature customer like me, hence the need for alterations]
Apart from the waist issue, the leggings are excellent. They feel very on trend, similar to, say Lululemon and Stella McCartney for Adidas. And the creative use of the pattern pieces makes them perfect for color blocking. The pattern pieces go together beautifully and the fit is great (apart from the waist that is!).
Since I’m crazy about mesh I changed the pattern and added a mesh piece just above the calf piece.
The pocket have room for the newer, bigger cellphones like Iphone 6 or a Samsung Galaxy, but just about, so making the pocket a bit wider might be a good idea. I also made waist band longer (around 2.5 cm/1 inch) since I don’t like narrow waistbands on leggings.
I also love how the Coras hug the bum, the fit is similar to compression type leggings. So despite my gripes with the waist, I can still recommend this pattern. Just make sure you check the elastic measurements before you cut the fabric!