I believe it would be entertaining and extremely strategically valuable to be able to watch back enemy raids.
You could see which of your heroes are dying first, which ones are using their specials more, etc…
In addition, I would like to be able to view another teammates War attacks. Largely for fun, but again, also for strategy. We can give each other advice on our tactics if we have a chance to watch their attacks. Many lower levels could benefit from this.
Of these 2 I believe Raid playbacks would be more feasible and should be the priority. But both would give us more to do without using energy or gems, would improve our strategy, and would be a lot of fun.
If anyone agrees that this would be a nice feature please give me a vote.