Why was nasus buffed

http://na.leagueoflegends.com/en/news/game-updates/patch/patch-621-notes#patch-nasus

Nasus is a quintessential juggernaut: a force of inevitability, a raid boss for the enemy team. There’s no question that he brings enough late-game damage to the table with super-stacked Siphoning Strikes, but damage doesn’t mean anything if Nasus dies before he can reach his opponents. So, rather than yet another source of damage, we’re retooling Fury of the Sands to give Nasus the ability to survive long enough to get into the thick of the fight.

because nasus was useless at the time

Wait... That was patch 6.21... It's 6.23 as of tomorrow. [zombie-brand-mindblown]

I still think he should have a cap, like 700 stack cap. Then maybe more will actually team late game.