Two things that really drew me in when I first played TW series:
1) The short video clips that would play to show your assassin succeed, fail and run away or fail and get caught, sometimes in a hilarious manner!! Please please can this come back!
2) the historical facts that correlated to the year in which you played, again sometimes with humour e.g. Rome, discovery of glasses and not selling them because they thought people would get picked on for looking silly etc.
Loved that I actually learned stuff about the era and area on which the series was based!
Would love to see these brought back!