Sahara,
I've just had a look at the "Fall of Berlin" Russian figures. Granted some of the WS figures have sleeves rolled up, but I reckon you could still use the Russian figures with the new WS sets for, say, Spring/Autumn 1942 ~ 1943.
Cheers
H
Hi Sahara,
Like Harry said, the WS figures would work just fine for dioramas depicting some of the early to mid-war fighting on the Eastern front, probably up to and including the Battle of Kursk (July 1943) which had a very significant Waffen SS presence on the German side. As has been pointed out, the uniforms worn by the new figures would probably preclude actual winter scenes, but Spring/Summer/Autumn would be more than appropriate, especially the first two.
The Soviet Fall of Berlin figures would seem perfect for opposition; they're featured with fairly generic Red Army uniforms and equipment so are more or less equally as appropriate for some of the earlier Eastern battles as they are for Berlin in '45.
As regards using the new figures for D-Day or later; at a pinch, they could work, but judging by their appearance and equipment, it would seem that K&C is going more for a depiction of early to mid war SS, so June 1944 might be stretching that a little bit too far. Weapons featured like the MG34 machine-gun and the Mauser C96 pistol (which seems to have been unique to the early-war SS, a very nice little detail from K&C) would probably have been phased out for frontline service in Waffen SS units by D-Day, in favour of updated models like the MG42.
You'd probably be seeing a wider array of different camoflauge items amongst SS units by this stage, rather than just the single pattern smock and helmet covers seen on these guys - different variants of the "peadot" pattern, as well as Italian camoflauge items were extremely prevalent amongst SS soldiers in Normandy.
Equally, items like the leather jackboots sported by all the figures would again by this point in the war have been in the process of being phased out in favour of the more economical ankle boots and gaiters combination (but that doesn't by any stretch mean that jackboots weren't worn by German units right up until the surrender in May 1945).
Whether or not you'd want to use them in this kind of scenario though is entirely up to yourself

!
Leaving aside the North African campaign, in which the SS (thankfully) never got involved in to any serious extent, your only other options would be the early-war Blitzkrieg battles. Discounting the German invasions of Poland, Greece, Yugoslavia, etc. (all of which the Waffen SS particpated in - but K&C don't as of yet make any opposition figures for these campaigns, so I suppose it's a moot point), this effectively means the invasion of France and the Low Countries in May and June of 1940. Here though, there's plenty of opportunities for deploying the new figures - they'd work extremely well matched up against any of the FOB British and French figures.
The 1st SS Panzer Division (Leibstandarte Adolf Hitler) was deployed quite extensively during this campaign, and saw significant service against British troops in particular, culminating in their appalling massacre of members of the Royal Warickshire Regiment at Wormhoudt in France. Equally, other SS units like the 3rd SS Panzer Division (Totenkopf) were engaged in considerable combat with elements of the BEF, again with deplorable consequences (the Le Paradis Massacre).
Another very good idea as suggested below would be to use these figures in a scene depicting some kind of Commando raid somewhere in Occupied Europe prior to D-Day, perhaps as a garrison in some Channel port, or as a combat unit resting up in what's (supposedly) a quiet area in Occupied France.
Anyway, there's definitely no shortage of possible uses for these figures if you are considering them. Hope this is of some help!
Cheers,
Molloy.