Webflow is a great tool, it could be used to build an expansive site for sure, but I wouldnt use it for ecommerce - thats a different ballgame. there is a limit on the amount of collections you can create in the cms, making a multilingual site is not really addressed yet, its not set up for managing payments - you would need to integrate lots of external add ons. There arent any ecommerce solutions as easy to use as Webflow either - regards altering the design - for best designed templates I would say shopify - it will cost though - and you need to know code to alter them.
Regards design though - I would say for a shopping site its all about the photography, so I wouldnt get to bothered about being able to adjust a pre made template - IF your coding skills arent up to it. A fluid, robust payment system is the most important thing. Shopify is weak on languages if thats an issue.
For language support OpenCart Ive found to be the best - I made a 4 language site a while back - you can find a good template on themeforest and take it from there. But the crunch with shopping sites is traffic, unless you are a big brand, I would consider a shopping platform like etsy/dawanda/folksy - or a more specialist one depending on what you are selling. On etsy now you can also create your own shop with your own domain that crawls your etsy shop and populates the site with the products. Styling is limited, yet minimal, so again - all about the photography - but you get the best of both worlds then - a site and traffic.
I would NOT recommend Woo commerce and wordpress, loads of hidden costs, and endless updates - slow and cumbersome - I know through my own experience! dont go there. Open cart now have something called opencart lite - look into that perhaps. what else Business Catalyst - with muse even - again, tried it, dont go there, just another adobe half arsed attempt at staying relevant.
I been on this journey a while now, Webflow is the best ive found for a designer - that and learning to code. a shopping cart solution that is as design friendly as Webflow is probably a few years away, but definately something thats needs to be made. Good luck.