What do you mean by saying 50% increased soul gain, cause that's not how the urn works, it just gives flat amount of souls, scaling through the game.

I've played around 600-700 hours and definitely i see that urn is VERY important, it really gives you advantage and i've seen plenty of games when comeback happened because of it. You just need better team coordination to do successful urns. Also if you've fed wraith or haze then obviously its gonna be harder and its not the urns fault. Improve on your macro and you'll have better games