This solution works, btw: http://wordpress.org/support/topic/attachments-not-included-in-cloud-results?replies=1 (adding 'inherit' as a valid post_status in the QueryBuilder.php file) but would still be better as an option or triggered based on post_type, I think

Do you know when post status inherit is used? Is it only relevant for attachments?

As far as I can tell (it's pretty incomplete in the Codex), it's only used for children of a post or page, so attachments, revisions, or sub-pages. Seems like mostly attachments but I guess there could be an edge case where someone might be intentionally displaying revisions, although I can't find anything in a quick search about whether that's possible on the front-end. For sub-pages, they typically have their own post status, but maybe there are cases where someone wants to use inherit to display them based on parent page status.

I ran into issues with your plugin where stragegy = current_list wasn't working (perhaps similar to this support thread: http://wordpress.org/support/topic/fetch-terms-base-on-the-current-list) - not using WooCommerce, but with a custom query on the page using WP_Query but would be happy to test further on a test site in the future if it's helpful.

Ok, so the safest solution would be to add post_status = inherit AND post_type = attachment to the query to make sure that only attachments are included. I will try that in 2.6 and then maybe you could test the beta version and see if it works?

Regarding the current list strategy I'm aware that it will not work in every case since it relies on getting the current $wp_query and calculating the terms from there. (code: https://github.com/rickard2/utcw/blob/master/src/Plugin.php#L565)

If you can find any other way to more accurately find terms from the current list of posts I'm happy for your help/suggestions.

First beta version is available now: http://downloads.wordpress.org/plugin/ultimate-tag-cloud-widget.2.6-beta1.zip

Or use WP-CLI:

rm -rf wp-content/plugins/ultimate-tag-cloud-widget/
wp plugin install ultimate-tag-cloud-widget --version=2.6-beta1