As for expanding the scenario options, you could use the BPV of the units involved to swap out nationalities. I've never tried that, but it might work, with some adjustment.
I would be more inclined to apply some of the later rules, especially concealment.
When I was looking through the scenarios only one struck me as probably not that fun--S9 Ambitious Assault.
It just doesn't look like a very fun experience for the Italians. You've got 12 MMCs with a morale of 6 and a broken side morale of 5. You've got three leaders, one with a -1 modifier and the other two 0s. And your ELR is 1.
Your objective is to have one unbroken MMC in admittedly a fairly large playing area. Your biggest advantage is having 5 machine guns including a heavy and medium, coupled with facing an opponent that for the first three turns has half as many MMCs and only 1 machine gun. But the Americans are monsters--7 attack, 3 smoke exponent, no ELR with 3 leaders, one a 9-2 and one a 9-1 for a leader-to-MMC ratio of 1 leader to 2 MMCs compared to the Italian ratio of 1 to 4. If you disperse your troops you can use your number advantage, but you really can't really stand up and fight; and any broken squad without a leader is probably going to stay that way until the end of the game. By contrast, to stand up and fight you have to concentrate your troops, but even two squads don't match the firepower of one of the Americans.
Then there are the British, which arrive on Turn 4--7 full squads, with a range five, which means they can stand off and shoot you but you can't shoot them without a machine gun. Even worse, they have three machine guns, with a minimum range of 7, meaning they can set up and the only weapons you can hit them with are the heavy and medium machine guns (of course a 3 factor squad with a range of 4 can shoot beyond range for an attack of 1 most likely on a building that has a +3 modifier; you could add the attack of a 2-5 machine gun for a total 2 +3). Of course, the Italians can take the balance, which is a single MMG--but is this really enough?
The Italians can definitely win, but is having a single MMC out of a force that is made to break, ELR, and stay broken, but somehow manages not to be broken at the end, a fun or even satisfactory win? To each their own.
I don't know how this plays out, and MMP is always very good about playtesting before marketing their materials. But if the Italians really are as bad as I would think, house-rule alternatives could be to replace the 3-4-6s with 3-4-7s. Or, with regards to what would be house SSRs, allow Italians concealment (per SK 4) and/or one (or more) "steeple" location (DaE, EP 1) in any multi-hex building building in the the victory conditions area, preferably a building on a hill.
For anyone who has only played SK before, you probably can't imagine how a second level on a building (steeple) or concealment changes the dynamics of a game. Other possibilities include Germans with panzerfausts (EP 1 4.4.2) in battles (only October 1943 and after) in which only their opponent has tanks. How about a few machine guns and concealment for Scenario S1; it would make getting past a lone German picket trying to prevent American reinforcements from entering the fray much more interesting.
If you find some of things disrupt balance, then you can just ditch them; after all, we are just talking house rules.
So, if I were to try to spice up the already existing SK scenarios, these are the kinds of things I would try.
