Hi,I know that this post is really old but in case someone comes across it like I just did, I can confirm that as a SEO consultant, I faced no problem whatsoever with WPML for SEO purposes. You can define unique title and meta tags with Yoast SEO for all your languages. You can even have the same image with a different alt tag depending on the language.
The only downside I have with WPML is it tends to get your WooCommerce website really slow if you have thousand of products and the translations get messy sometimes. I had to use their troubleshooting tools to resolve some translating issues.
