I don't know how everyone elses experience is. As a summoner, I'm currently winning every game I have with a tank on my team and losing every game without. Because I know that if I don't have a tank, I'll be a) hoping to win while noone in my team pushes the crystal or b) keep dying over and over as soon as I'm out of mana to heal myself while trying fruitlessly to tank the crystal against their mob.
Tonight was particularly jarring having this exact experience 5 times in a row, with a tank on the opposite side but none on mine.
Now I know already some will disagree with my statement here; and that's OK. Just please keep it civil. Other than that, would love to hear your opinions!