We started out talking about color temperature controls. Those are far and few between.
Dimmers, though are much easier to find.
The Sylvania switch that you mentioned can Be used as a dimmer, but only for zigbee bulbs, Only with the classic V2 app, and not with the official integration. See the following FAQ:
That said, Lutron has a new zigbee dimmer device coming out in a couple of weeks which is much much better looking and more intuitive than the Sylvania device. It also fits right over the top of the existing switch. It’s an official “friends of Hue“ partner so it works with the hue bridge. We don’t know yet whether it will work with SmartThings directly, we have to wait for the release to find out.
Lutron Aurora dimmer for Hue lights (Z3-1BRL)
If you hadn’t specified color temperature, I would’ve mentioned this one right away. It won’t give you color temperature control, but it definitely gives you a no wiring required dimming switch on the wall which covers the existing switch and looks just like a regular switch. 
(It’s very important to understand that while a color control switch might look the same as a dimmer control switch, it is sending completely different commands. This is true whether it is Zigbee or Z wave. So the physical switch itself has to have firmware that will send the right commands if you want to be able to use it for color temperature control.
Alternatively, if you use the “scene” concept instead, then the physical switch can be any design as long as it will send a scene number to the hub. That is what devices which smartThings calls a “button controller” usually do. Then it is up to the hub to have programming which knows what to do with that scene Number.
So maybe Scene 1 is your normal “evening” settings for both brightness and color temperature. Scene 2 is “ movie night” and both dims the lights and makes them cooler. Scene 3 Is “task work” and makes the lights very bright and cooler. And so on. Each scene is a set of presets which could include multiple devices at different levels if desired. And multiple settings for each device.
Scenes work well for many people, and in fact, some people prefer them. They will give you more choices for switch type on the wall. But I understand that you might prefer to individually adjust both color temperature and brightness. Choice is good, it’s just that there aren’t a lot of choices for color temperature control at the present time.
