I've never heard a convincing argument for the necessity of cascade. If I recall correctly, the reasoning last time this was discussed was that more testing was needed to determine the impact of removing cascade negate from the game.
This.
Is there an ability or strategy that is believed to take over Redemption should cascade negation be removed? I'm not saying there isn't - just that I haven't heard of one, nor can I come up with one off the top of my head.
If cascade negate was removed from the game tomorrow, I'm trying to think how my decks would change... Not sure any big changes would be warranted. Or even any changes at all. It would just be more fun because more of my cards would work, and the purpose of playing Redemption is to use your card abilities