A recent importance doesn't really matter. Sakurai can and will do whatever he wants when he wants, BUT that is what the Ballot is for hopefully. A chance for us to actually pick who we want. As long as the Smash Ballot isn't a Kroc then all should be well.
Yes. He CAN chose a character at random. But all of our newcomers have a fairly recent title or are a retro. Edit: Now that I think about it... I think this rule can basically be held for the newcomers in EVERY Smash title, with
![N64 Ness :ness64: :ness64:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![N64 Falcon :falcon64: :falcon64:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![N64 Samus :samus64: :samus64:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Marth Melee :marthmelee: :marthmelee:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Olimar :olimar: :olimar:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
and
![Little Mac :4littlemac: :4littlemac:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
having some of the largest gaps.
![Villager Male :4villager: :4villager:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: City Folk when chosen for the roster. New Leaf being released weeks before the game was announced.
![Megaman :4megaman: :4megaman:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Gaming ICON with last game being December 2012, with Street Fighter x Capcom.
![Wii Fit Trainer Female :4wiifit: :4wiifit:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Wii Fit Trainer Male :4wiifitm: :4wiifitm:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Wii Fit U.
![Rosalina :rosalina: :rosalina:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Super Mario 3D Land, Mario Kart 8, Mario Galaxy 2.
![Little Mac :4littlemac: :4littlemac:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Punch-Out!! Wii, honestly the "oldest" of new titles on this list.
![Greninja :4greninja: :4greninja:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Pokemon X/Y, was chosen from CONCEPT ART before the game was released.
![Mii Male :4mii: :4mii:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Tomodachi Life. 3DS Street Plaza Titles.
![Palutena :4palutena: :4palutena:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
/
![Dark Pit :4darkpit: :4darkpit:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Kid Icarus - Uprising, the game Sakurai was working on months before he started development on Smash 4.
![Pac-Man :4pacman: :4pacman:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Was honestly chosen as a retro, but we technically have Ghostly adventures.
![Robin :4robinm: :4robinm:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Robin :4robinf: :4robinf:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Lucina :4lucina: :4lucina:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Fire Emblem - Awakening
![Shulk :4shulk: :4shulk:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Xenoblade Chronicles
![Bowser Jr. :4bowserjr: :4bowserjr:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Larry :4larry: :4larry:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Roy :4roy: :4roy:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Wendy :4wendy: :4wendy:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Iggy :4iggy: :4iggy:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Morton :4morton: :4morton:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Lemmy :4lemmy: :4lemmy:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Ludwig :4ludwig: :4ludwig:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: New Super Mario Bros./Luigi U.
![Duck Hunt :4duckhunt: :4duckhunt:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
: Retro.
I'm not saying King K. Rool is unlikely because his last role was a 2009 (?) Mario Spin-Off game. Infact, he is top 3 of the Ballot if we disregard Roy and Wolf who are all but assured to be DLC confirmations before the ballot comes to a close.
But while it may or may not matter, it IS a present factor. A trend. Correlation does not mean causation but it's something that can be noted.