What's wrong with hive minds? As long as my 'soul' survives, I wouldn't mind being part of some gigantic consciousness.

A hive mind can quickly lose a lot of old human values if the minds continue past the death of individual bodies. Additionally, values like privacy and self-reliance would be difficult to maintain. Also, things we take for granted like being able to surprise friends with gifts or have interesting discussions getting to know another person would probably disappear. A hive mind might be great if it was formed from all your best friends, but joining a hive mind with all of humanity? Maybe after everyone is your best friend...