Punxsutawney Phil's Phylactery of Woe? The Groundhog Lich-King casts a pretty long shadow! lol
CR and XP tables/scaling handles everything, provided they approached the various combats as "encounters" rather than as set-piece battles where the enemy is all prepositioned like it is currently.
Not to get too sentimental again, but it's funny to me that two of my all time favorite games Axis and Allies and Baldur's Gate, both suffer from the same set-piece design sensibility in the starting conditions (and now the two have kind of merged into this strange mirror universe nostalgia with the Enhanced Editions in BG functioning sort of like Special Editions in SW, by adding stuff that we now have to accept just to play in a modern format heheh.) But the thing that strikes me about A&A is that it suffers from a lack of variety due to not having enough variation in how the board is set initially, or randomizers to make the opening play patterns more unique from game to game. And in BG you get something very similar with the way combat encounters are designed. With the same starts, and the same sequencers, same enemies and positions and loot. So the game becomes stale quickly like that, because the play patterns become so similar over time and coalesce around whatever the most OP play might be for that encounter. It becomes about breaking the game through the meta of already knowing the script, when the basic systems and rules could allow for much more (probably an unlimited level of replay if it just had a few more randomizers built into it on the fly). Clearly not an identical dilemma, but its similar.
By using CR tables with randomizers you could do a lot to make each playthrough feel unique without having to put a thumb on the scale for everything. I mean you can still have the main NPC Opponents and boss fights that drop the known Loots and such, but they could easily mix it up in the trash mob cascading combat parts that they seem to enjoy toying with. They could do the same with arena environments and instanced encounters, even on the aesthetic front with unique gear. Done properly it could scale from a party of 2 to a party of a dozen, since that's why those tables and systems were created to begin with.
I'd still prefer 6 as the default for the single player game.