I'm just echoing a plea by many paid users whose primary support platform is Linux.
One of the very great attractions of TeamViewer for me in the past as an independent IT administrator was the fact that it was so full-featured, performed extremely well, and best of all, functioned identically across Windows, Linux, and Mac platforms.
Also, the past purchase model for licensing rather than a subscription model was a win too. I didn't mind shelling out $700 for a license and would have happily paid for upgrades from there, had the user interface consistency been maintained.
So much for the myth of a lifetime license. Sigh.
But from starting with TeamViewer 12, it seems as if Linux had to take a back seat on new features that appeared in the Windows version. For one example, consider Remote Notes, which is extremely handy ... if you're doing support from a Windows platform.
I hope with TeamViewer 13, there will be a real and successful effort to match features and interface consistency once again across all platforms.
But it may be a moot point for me, because with the new subscription model for pricing, it's a real stretch for me as a sole proprietor to find TeamViewer to be worth the expense. I can see how it makes sense for enterprises, but it leaves we independent support specialists out in the cold.
TeamViewer is a great product, with the caveat about Linux, but there are plenty of lower-cost and even free alternatives that do almost as much.
So c'mon, TeamViewer, get back in the driver's seat as the best of the best. As a former software developer, I could tell that you had it together in the past.
Don't let marketing take over and run the whole show. 
Regards,
Jim Hopkins