Amazon has only disincentives for giving you TTS. They want you to buy audiobooks and hopefully listen to them on the Fire. They still sell the kindle keyboard, I suspect, to ward off potential complaints/lawsuits from the disabled. With no audio, what do you need more memory for? To side load all your books? Nuh uh, they want you to get used to putting everything on the cloud. Don't be a control freak. That is their job.
We will probably see an improved front light system. Plus more software features like X-ray.
The kindle is bound by eink technology. Lately, eink corp. hasn't done squat to advance their display. And nobody else has brought anything to the market to challenge them.