Just a few things that would improve YAC overally:

1. Switch database to LevelDB - faster startup and shutdown, less chance for data corruption.
2. Increase number of full nodes that accept incoming connections - currently my node can't find even 8 of them after few hours online.
3. Use different wallet look and feel - check Silkcoin or N5coin, integrated blockchain explorer and statistics are just awesome addition.
4. Aliases - user creates an alias and assigns YAC address to it via special transaction, later to send coins to user one could just use alias instead of normal YAC address.