The last several Intel generation performance gains have been marginal. I don't expect Kaby Lake to be a huge performance gain over Skylake, just a tweaking and marginal upgrade over Skylake.
as the title says will kabylake be a big improvement over skylake or should i wait for cannonlake
As far as I know Kabylake will not be a huge jump, it is essentially an updated skylake architecture on the same socket.
There will be very marginal gains over skylake, so if you're building a PC, go for skylake now, and if you're waiting to upgrade wait for cannonlake unless you're an crazy enthusiast and want the top speeds on the market.
Agreed, the i3 6100 is a solid CPU for the money, should last you another year and a half or so before it starts to bottleneck on the latest games when they start to utilise more cores, so you should be good! ^.^
The last several Intel generation performance gains have been marginal. I don't expect Kaby Lake to be a huge performance gain over Skylake, just a tweaking and marginal upgrade over Skylake.