Given the age of Sam Fisher, we can't honestly expect him to be the main star of every Splinter Cell game unless Ubi intends on ending the franchise.  If you magically had your way, who would you make the heir to the Splinter Cell throne?  More specifically, name, gender, physical traits, and most importantly voice actor for this character.
i.e.
Name: Dova Pillager
Sex: Female 
phys:  Built like a lethal super model
VO: Zoe Saldana 

Irving Lambert.

Micheal Westen, as long as he starts every chapter with "When your a black ops agent" and narrates what each of his gadgets do. 
 
edit: voiced by Steve Blum or Nolan North

A few years after the events of Conviction Fisher starts up a new 3E and in his first mission he has to go to Russia to find a WMD and to see if it's really been stolen by Terrorist.  
  
Places To Be 
 Washington DC 
Moscow 
Iraq 
Africa 
New York 
LA 
Las Vegas (can meet up with the rainbow six team here) 
Washington DC 
 
Splinter Cell: Breakdown

A wisecracking "everyman" who brutally  murders hundreds of people one second and jokes around with his love interest, who doesn't even comment on the fact that he's a homicidal sociopath, the next.
 
Voiced by Nolan North.

" A wisecracking "everyman" who brutally  murders hundreds of people one second and jokes around with his love interest, who doesn't even comment on the fact that he's a homicidal sociopath, the next. Voiced by Nolan North. "

" Micheal Westen, as long as he starts every chapter with "When your a black ops agent" and narrates what each of his gadgets do.   edit: voiced by Steve Blum or Nolan North "