You make a very good point how 
First Level could be overpowered by 
Turgon...that would get out of hand if they combined healing techniques from a first serie deck with this. 
City Wall, on the other hand isn't unique and can be combined with 
Take Cover.
Boromir, Stewards Heir, by himself does a solid job of bridging the gap between Knights and Rangers, like you mentioned. Since we have decks with ranger theme, by focusing more on knights with this deck, someone would be able to combine both at whatever level they would like. It would really be nice to see the Knight starter deck really provide you with enough Knight material to be able to go all the way with them as well.
Here's what I had in mind, its only slightly different from your most recent deck:
2x 
Boromir, Steward's Heir2x 
Gondorian Knight2x 
Turgon, Man of Belfalas2x 
Dervorin1x 
Banner of Westernesse2x 
Knight's Mount4x 
Sword of Gondor2x 
Hobbit Sword2x 
Dagger Strike2x 
War Must Be1x 
Reckless Counter2x 
Take Cover1x 
Citadel of the Stars4x 
City Wall1x 
Garrison of OsgiliathReasoning for some of the adjustments:
Since this is a proposal for a second serie deck, you would only need 2x 
hobbit sword since you already get 2 in the first serie, no matter what deck you choose.
Only 5 companions other than Frodo - again since they will already have one deck to work with, they will have no problem getting 9 companions in there, so the companions offered in this deck can be a little more exclusive to the theme.
There aren't as many skirmish event pumps, as 
City Wall functions as a pump in and of itself. Or, it can alternatively be used for wounding with 
Take Cover (the Knight's version of 
New Errand, kind of).
The deck is a little more straightforward companions/possessions/pumps now, with a few neat Knight-related twists.
Some site liberation involved to keep in theme with the norm of starter decks being paired with shadows that they perform decent against.