In October, Google will hopefully hold an event where the manufacturer is likely to showcase a new Chromecast. That's one thing I really hope for when it comes to this device.
What I hope for is that the new Chromecast will bring improvements when it comes to Stadia. As it looks right now, you need a pretty good Wi-Fi to get Stadia to flow well in the interface. This is something I hope Google has worked on so that in the future you will be able to play in the same awesome quality, though with slower Wi-Fi.