I have trained 128'000 soldiers - which depleted all my resources available and everything from some personal / clan / premium task (even refreshed tasks). Since I can train about 4'500 soldiers per cycle (which takes ~9 hours with a 30% troop training booster), I've spent twenty five 3 hours boosts, to train these troops effectively.

The reward in the troop training: 0

Yes, it's zero. Nothing.

I am about half way through the "League of Rookies" which is on the lower end of the scale. Still, even after using boosts worth 16'625 gold (665 gold per 3 hour boost), I am only 50% towards the 200 gold reward.

Maybe this needs a little tuning?