I am a programer and I can promise you that, you can use Blueprint to make any gameplay logic.(Networ function is not that good, I even cannot find the right node to rename my server.)
But the problem is Blueprint runs far more slow than c++. Tiny project is fine, but when your project get lagger, the performance will be poor.
4.12 released a new feature which can convert Blueprint to C++, but it is still a beta function. Hope Epic will do better.