Sylas R cd should be nerfed (at least in aram)

It's crazy how sylas can use up to 3 powerful ultimates in the same teamfight. Sylas R cd is 15 seconds at lvl 3 (without cdr items) so last aram I played he could use the ultimate from galio (160 s. cd) brand (75 s.) and TF (120 s.) in just 25 secs. Its fair he can take the r he wants ,in fact its the essence of the champ, but the independence of the cooldown is just no sense. Of course we lost the game. He got a penta.