I'm all for more events, but I don't think there are any puzzles worthy of the wca right now. For a puzzle to become a new event, it has to bring something new to the table, and there has to be a large number of people speedsolving it for a very long time. The hype around both the Redi cube and kilominx has died down though, so I don't think either of them should be made events. I would prefer redi cube over kilominx, however.
I would say kilo. Redi would be awesome, but kilo at least has a relationship with another WCA puzzle (mega), some with kilo we would be getting something new, but not something thats completely off the grid.
Neither. I don’t think either of them bring anything new or fun in. Redi cube is basically just spamming pyra comms and kilominx is just megaminx but easier