Take a look at your preferences - there's a performance setting in there. Make sure it's set to the same as Photoshop CC.
However, if you have CC and CC 2014 - you can just launch Photoshop CC and use that for the time being.
If you feel it's a bug then file a bug request - Adobe - Feature Request/Bug Report Form
My performance settings are the same for CC and CC 2014.
I assume the problem is introduced by the changes/improvements of the Content-Aware tools and on normal file sizes it might not matter for the user if the operation takes 25 or 200 ms. But on large files it seriously slows down the retouching work.
So far I've been doing as you suggested, using CC for that type of work. But as it takes about 90 minutes to save these huge files and AFAIK Photoshop CC and CC 2014 cannot be run as separate instances simultaneously it's quite inconvenient not being able to use CC 2014 for some other type of work while CC is saving the file.
If the new Content-Aware functions take that much more processing it would be great to have a choice (similar to the choice of the RAW-engine used in ACR). However, if the new Content-Aware functions are just not yet optimized for fast performance then it's a bug.
I will file a Feature Request/Bug Report and ask if there is anything that can be done about it in Photoshop CC 2014.
Thanks for your help, Eugene.
You can run both programs at the same time - there's no issue with that at all. Run them side-by-side if you wish.
Have you tested the tool on smaller images?
At images up to 200 Megapixels I have not felt any slow-down of the Content-Aware Healing Brush compared to Photoshop CC.
How can I open Photoshop CC 2014 when I have Photohop CC already open?
When I try to open CC 2014 with CC already open I get redirected into CC. This is on Windows 8.1.