Overall, for a TS Sealed league, I feel like it would be nice to launch some starters that have themes that have not been touched on at all with the existing sealed decks.
As far as Shadow goes, there will always be
some repetition, but I really think there are some combos or strategies in general which would benefit from having their own starter. In the end, everyone would be having some fresh experiences, working with combinations of cards that they probably have not in the past

I'll just throw down some of my ideas to the list, going serie by serie...this doesn't mean that I think that one deck would be limited to that serie in particular...it might just fit there a little better.
I'll
underline the ones that I feel stronger about. Let me know what you think and please post your own!
FoTR / TTFELLOWSHIP
Rangers - a combination of the rangers from FOTR Block, and maybe a couple Ringbound ones from TT. Splash a
No Stranger to the Shadows or two and some
athelas
Rohan/GandalfDwarf/GandalfShoulder to Shoulder - I think a starter deck centered around this card would be very cool
Gondor/Stealth HobbitsGandalf/Stealth HobbitsSHADOW
Isengard Trackers - Maybe include the one tracker from RotEL and throw in some
Saruman's Ambition...
EasterlingsDunlandSouthronMoM/BoHDFELLOWSHIP
Elf ArcheryGondor Knights - I think a starter based on knights would be cool...even if the pool is limited, you could add some support from FotR Block
Smeagol/Hobbit ChokeRingbound CompanionsSHADOW
Twilight Nazgul - I really think its time for these guys to make their debut. They may not be the strongest, but with some support from
Fell Beast and set 6 Nertea, they
should put up a fight in a Sealed environment. Would be a lot of fun.
Sauron TrackersArcheryWarg-Riders - Maybe these guys should get left out since they already have a starter? Maybe they could be combined with something?
Berserk Uruks and MachinesRotEL/EoFFELLOWSHIP
Last Alliance - Elves and Gondor companions
Help in Doubt and Need - Rohan and Gondor companions
Shire Pipeweed/Dwarf Tanks - just trying to think outside the box, haha
Ent HordesSHADOW
Sauron DiscardingGollum/Easterlings - combine Easterlings with the Gollum and his events that add burdens and wound for skirmish wins.
"Stupid Swarm" - This would be the classic combination of Isengard and Moria orcs
News of Mordor - Nazgul and Isengard minions (possibly orcs like
Isengard Smith)
Also, as a general discussion topic, what are peoples' thoughts on including
Cavern Entrance in one of the starters. In the TT sealed, it doesn't look like it shows up in any of the starters...maybe because it is so powerful a card? What does everyone think?