This was suggested as part of another thread, but figured it might need to be a thread of its own and expanded on a bit.

Make a recessed lighting fixture that's basically the features of the KL135 (or whatever next-gen RGBWW light might follow), plus a few extra features.

Primary user story: 

As a user with 4-, 5, or 6-inch recessed housings already installed throughout the house, I want bright, colorful, smart lights to install in them, so I can make the most of these pre-existing housings. The standard A19 standard-bulb form factor is not ideal, as the light it can spread below and around the recessed housing can be limited by common trim depths and styles. 

BR-style bulbs might be better, but both standard A19 and BR-style Edison base bulbs will have engineering design and production limitations that prevent the addition of physical features that would greatly add to a dedicated ceiling light's functionality.

An ideal form and functional requirements for these recessed light replacements might include:

• A shallow, 4-to-6 inch round form factor that incorporates all electronics and RGBWW LEDs.
• 1200 lumens minimum, color range at least as good as the KL135
• Two-wire tinned power leads with included Wago connectors and a two-wired E26 base adapter, for easy installation in any housing.
• The back of the product is, ideally, flat, to allow the most mounting options. If a power supply/driver must extend beyond the back plane of the PCB, the depth should be kept to 1/2-inch or less, and the area it occupies should be centered and kept to less than 3 inches, for compatibility with shallow mounting locations or junction boxes.
• The light itself is housed in an assembly that serves as its own basic, reasonably attractive trim ring, serving by itself to cover at least a 4-inch recessed light housing or junction box opening. This should easily replaceable with included, option rings up to 8 or even 10 inches to cover openings for larger housings. 
• Ability to connect or attach to 4-, 5-, or 6-inch housings via attachable leaf springs (for smaller housings) or tension springs (for larger housings)
• Included 5- or 6-inch diameter, shallow, mounting ring base that can be installed on 4-inch lighting pan or junction boxes, or two-gang junction boxes, on which the light can be mounted or un-mounted with a quarter- or half-turn twist. This makes it useful for a plethora of additional installation applications that are not a recessed lighting can.
• User-selectable and installable options for flat and domed, frosted diffuser lens. Flat for a slightly expanded light spread compared to standard recessed lighting; Domed for more expansive spread providing wider coverage across a room or along the top of nearby walls.
• Built-in motion sensor that can be enabled or disabled, used to trigger the light itself or as a sensor to trigger other lights or devices in a group or smart action
• Built-in ambient light sensor that can be enabled or disabled, used alone or in conjunction with motion sensing, as a trigger for the light or other lights or devices in a group, and to adjust brightness or color temperature for the light or other lights in a group in response to room light conditions
• Built-in Bluetooth for the sole purpose of being able to reboot, network reset, and factory reset the bulb without having to toggle AC power or physically touch the light. Alternative is an IR sensor for this purpose, but A) it must have a unique NEC Device ID (not just "x0000") to avoid conflict with other common IR remote controls, B) should require a several-second long-press as further protection against triggering by other common IR sources, and C) any included or available IR remote control for this purpose should have a focused, narrow IR beam, so a single light can be targeted in a room full of lights.

Yes, it would make for a pretty extensive feature set that would easily place its cost at 2.5x - 3x that of a KL135. But I've used lights that had nearly all of these features except for RGB colors, and with a proper method of keeping them in sync when grouped, they are amazing. It's easy for any such light in a group to keep all the lights on with motion sensing, no matter how the room is entered or occupied - no more standing from the couch and waving at your motion sensor wall switch from across the room. In rooms with lots of windows, the lights can dim when the outside light is bright, and become brighter when outside light wanes. With a BLE or IR reset method, fixing that one light on a high ceiling in a room with nine of them becomes trivial and doesn't require dragging out the ladder.

The installation flexibility means they could easily be used in numerous areas and in creative ways that would be near-unthinkable with standard format bulbs. Recessed lighting in AC-powered cans is obvious, but they could also allow recessed-style retrofit lighting using only old-work junction boxes, easily replace those contractor-grade 1- or 2-bulb dome fixtures seemingly found in every house in hallways, bedrooms, laundry, and utility rooms. I've even mounted designs similar to this on walls, as sconces and vanity lighting. Make it at least humidity-resistant, and they'd be great in bathrooms and showers.