I am running an e-commerce website which sells designer dresses (around 80 different models). Most of the traffic currently comes from Facebook ads. Do you recommend to create landing page for such a business or send traffic to the /shop/ page with all models? Which sales funnel would you recommend for fashion ecommerce web-site?
I would consider every product page on your site a landing page worth driving traffic to. Almost everything you would do to optimize a landing page for performance can be done to your internal site pages. This will 1) help you get better results from your existing pages and 2) save you time from having to optimize multiple pages for the same thing.
Your Product page is your Landing page. But not the only one.
You should give it a try and create landing page for a category or sub-category (i.e. women winter collection - just guessing what it might be) where you present the products in different way than it's usually possible with standard e-commerce product page (videos, animation, story telling, video testimonials, interactive elements etc.).
Then evaluate the New Landing page performance compared to standard Product page (but make sure it's still optimized and treated as Landing page).
A facebook ad should always lead to a landing page that is designed to capture an email address. Then you can pull your clients into a nurturing funnel. It is not realistic to expect a facebook ad to bring in a sale. That is like asking someone to marry you on the first date. This why you want to capture the email address immediately and begin to date this person and gently lead to through a sales process.