Look ! Currently I am busy with my last 2 years at school. After that I am free. In June 2018 I will start working on my big games. I made small games this year that I am not going to publish. Just learning construct 2 by making them !
So what you suggest buy license for construct 2 at 2019 or Wait for construct 3 ?!
Construct 3 will take more than 4 years from now I guess !
Maybe it will be in 2021 and it may contains bugs and problems at beginning !
Shall I buy stable construct 2 licnese ?!
Since you are asking for a future purchase advice (2 years from now), my sincere answer is: I don't know. Probably till then Scirra rains us with information so you can make your decisions accordingly. However, if you would ask should you buy C2 now or wait for C3, then I'd say go and buy C2, since we don't have any information on the latter.