I was reading a bit on Yamato after I saw a documentary about her on Youtube the other day and since I like what-if subjects here is my suggestion...or shall we call it brain fart?
Yamato did not sail to rescue Okinawa but did fall into Allied hands at the war's end. For the same reason the emperor of Japan was left in power, Yamato was not used as a target during the A-bomb test but was mothballed in Bremerton. After Japan was becoming a solid democratic and trust worthy partner (late 50ties?), Yamato was returned to Japan. Now there were 3 options crossing my mind...
1. Most likely...she became a museum ship and is one still today
2. The Japaneese Navy put her back on duty and modernized her...she since serves as flag ship and is still on active duty...maybe now (2015) in a similar status as the USS Constitution. Up to what stage would she have been modernized? Maybe mid 90ties? How could she have looked?
3. She became a space ship...
The most interesting discussion point I guess would be No.2...if that is worth a discussion at all?
cheers
Uwe