Kassadin buffs

Everybody's favouite kassawin needs some sorta buffs to be considered strong again, as there are currently several champs that do his job much better for him (TP Akali etc).

Maybe letting the 20 sec stack retaining go down with CDR? that way at max CDR Kass would hit the 12 second's it was at before last nerf. Alternatively letting him get an extra stack before reaching 1200 for each time he ranks R? Eg. 40 mana cost at 11, and 20 mana at 16. or similar. His main problem is that a 1200 mana cost is just so ridiculously prohibitive that you almost can never use riftwalk freely, for fear of getting into a fight and actually needing to be at 0 stacks.