Hmm, how about a reboot completely forget the name Assassin Creed get rid of Desmond and the Animus. Start a new franchise.. I want the Graphics of Assassins Creed set in England.. Call it Robin Hood (free ready made well known franchise, I presume nobody owns the rights to Robin Hood!)
You play as Robin Hood and maybe his men too!, have towns, castles, villages, forests, you could have different types of enemies.. Tax Collectors, Barons, even Templars, Sheriff, Normans with shields, correct me if I am wrong but I don't remember Altair fighting against anybody with a shield in AC1 or Ezio AC2.
Cue FMV of Normans killing your family as a child just to get you in the mood for some payback. Then your in the dungeon years later, first mission escape the dungeon, get training and then recruit your men.
Rob the tax collectors to help pay villagers back, attack Normans, enter tournaments, hunt deer, help starving villages, don the armour of soldiers, rescue people from the noose, I'm sure someone else probably could do a much better mission list than me..you get the idea!
Robin is a lively spritely character (no armour), who can do everything climb up buildings, use sword, bow, quarterstaff, against enemies with shields, crossbows, and on horseback..
There is a lot of scope for a good action and a smidge of RPG too!.. and as Comabob said spend less time in menus. Still even If one person backs me up on this. I'll still be pleased.
This post is probably riddled with errors, sorry but I got excited!