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I'd say it''s all down to content and how much of Good Relevant content you have. If you have enough content to fill a website about all of these individual areas then a sub domain offers you the ability to demonstrate your expertise in these areas and Google will see that your focussed in that area. Also it means that the first word will be a keyword in your domain which is excellent. However if you have only a few pages for each site that would be bad as Google would see it as it is your making something solely for Google ranking which it would very much frown upon. If your doing something to your site just for Google ranking then generally as a rule of thumb the answer s no don't do it. A well structures site is much more preferable.

Check the homepage to see if it ranks for some other things; the domain name without the www the domain name with the www the title tag with the title: operator cut and paste a string of text (maybe 12-15 words) and search for it in quotes the OLD brand term (you said this was a re-brand as well?) the OLD domain name What do those all return? Further; Does the homepage show as a landing page in webmaster tools? Does it show getting traffic from search in analytics? Does it rank for anything in Bing or Yahoo? It sounds like more diagnostics are needed before we can conclude anything

My suggestion would be to go beyond creating 'yearly' top lists for the site (these are old and tired). Look to create an 'Evergreen' content page that you can use and leverage year over year, build on and create a community and discussion around. Discuss the changes each year by revamping the list, ask people their input (UGC) and discuss why some of the one's that fell, did, while also pointing out new one's didn't fall and why By creating a page like this - you leverage the long term effect of a page that never gets old, or outdated (as one does with regards to a specified URL like 2012 or 2014) in your examples. This will also help you create a very strong profile from a backlink perspective as your links will accumulate into 1 evergreen/lasting URL - that never gets outdated with yearly updates you will make. Might want to use the META information for data posted and date expired to ensure that the crawlers know to come back and recrawl when a page is live. Ensure it's mapped and setup properly in the Sitemap XML file too I think the advantages of moving towards this will help your link profile, leverage a great piece of content year over year, making it move 'sharable' from a social media perspective and leverage long-term value. Just my 2 cents to help you out Cheers, Rob

I wish I could accurately place this on a scale for you.  In my opinion I would consider this to be white hat.  You have no intent of manipulating search results here - this is completely a usability issue and this is the obvious fix. Yes, I certainly would yes, I certainly would