When you ask a JW why hasn't God brought an end to the old system it is because He is being patient and he wants everyone to have the opportunity for everlasting life. They will say that every year over 200,000 become JW's (most of whom are born ins)
The problem that I have is that every year over 130,000,000 people are born which means that every year He delays in destroying the nations there will be 130,000,000 more people to murder and bury. That doesn't sound very loving to me. If he waits another 8 years for the great tribulation add another billion people that he has to murder while adding another 1.6 million witnesses who will be on the burial duty.
The Bible says that God is love yet every day he permits over 20,000 people to die of starvation. He has the power to fix that and He doesn't.
That just leaves me Sour Grapes