The whole domination tree is just horribly designed.
It's just a tree based on getting as many kills as possible to make your runes even stronger. A fed champion gets way more benefit from the domination tree than an unfed champion. This leads to something called "double snowballing", where not only you snowball because of more gold and exp, your runes snowball as well. In the old rune system, everyone got the same benefit from runes and masteries regardless of how fed they are.