Shopify is very trigger-happy to remove your site and payment processor, as I found out about the hard way.
I actually just spend 1 1/2 hours on the phone with them today, and even they agreed that the "frauds" team went a little overboard on my account. I also had to talk to them about horrible integration issue with different apps, which isn't surprising. The Shopify API is plain awful, and nearly every app that I've installed has broken in spectacular ways. I had to re-import all my products two weeks ago, which was just perfect timing for Christmas. These app issues also caused me to do too many refunds, caused fees from eBay, and generally made this month a wash.
Working with the Shopify ecosystem really isn't so different from working with WordPress. To get a good design cost a lot of time and money due to broken plugins. What's funny is a lot of those plugins require you to do your own custom coding to get them to work at all.
Facet sorting by color, size, price, etc, is either totally impossible or very expensive as well, but BigCommerce has the same issue. A facet-enabled site on BC is $300 / month.
Reality is that ecommerce at any appreciable scale (more than 1k / mth in sales) is completely broken, and it's only made worse that few developers in this space are worth much. That's a function of trying to sell apps to an industry where about 10% of people work in the black, but then again, most apps, plugings, channels managers, and so on, end up causing massive issues (and can even blow out entire month of profit), so the cycle continues.
The other problem is that selling online is a revolving door. It take extraordinary work and knowledge to get the levels I'm at even. I'm a small dog compared to a decent-sized eBay or Amazon seller, but compared to the typical Shopify person, I'm a total beast. Everything is optimized to the smallest common denominator.
I would love to continue working on my idea, but reality is that I know there aren't many devs who have knowledge of the space, plus it's the same issue one finds when trying to build for the restaurant industry: how do you turn a profit in an industry no one earns money?