I don't think it's a con, I think it improves the team aspect of the game. An alliance should have to work together as a team to win. It will also promote chatting in alliances about how to attack etc which is good for the social side. It shouldn't be just a bunch of players doing individual attacks.Cons: Enemy alliances are now tipped off about our trap placements and troops hiding in our town centers.
This functions is good. However, it is a lot better if not everyone can see the replay. If it can be like the multiple play which only can be replay by the one who attacks and who is attacked. Reason is some high end players might spent a lot of time in attack strategy and don't want others to see their secrets. Another reason is for the bases which arranges very good traps. If someone attacks and the rest can see where the traps are. It will be unfair for that base.
Digging the war replays. Though I can see both sides. It's nice not to have to wonder if the opponent is smashing a base with card spam or cheats. However, I predict a lot of decoy spam and switching to Brandenburg Gate after seeing how obnoxiously effective that combo is for the first time. So there's the hidden strategies part. It's laughable that sab/protect/betrayal were nerfed when that's allowed. May as well reap the benefits though.
A bittersweet revelation for sure.