Portsmouth has plenty to offer, as mentioned theres the Spiniker Tower, Historic dockyard with HMS Victory, the Warrior and the Mary Rose, theres also the explosions museum just a short ferry trip on the gosport side of Portsmouth Harbour, and great shopping to be had at the new prestidgious Gun Wharf keys complex as well.
Pubs and restaurants are abundant.
Only one draw back i can see, IF Portsmouth becomes a chosen venue, make sure its not when the football team is playing at home, (no im not a footie follower) the ground is in the city, and entry to the city becomes a nightmare as does parking.