It would be great to be able to link switches directly so they control one another when 3-way or multi-way wiring isn't available.

Insteon light switches were able to be linked directly (I linked up to four switches together).

Only one switch needed to control the light, while the other three only needed power.

Switch linking (up to six switches or more) would be a fantastic feature for Kasa so you wouldn't have to run multi-way wiring.

This would also eliminate the need for the 3-way kits.

The idea would be to hook up one HS220 to control the actual light.

You could then install a HS220 switch anywhere that has a neutral, line, and ground to give it power.

No need for travelers.

I would buy a ton of these if they had that feature. I can't use 3-way kits in 4-way and 5-way installations without buying multiple kits.