Hello Eskuche,
In almost every update small changes in scenarios are made. Adding a prototype, change some unit names, add a historical unit or something. Sometimes the changes are important like if victroy conditions are not good or other errors. In the next update there will be a major Stalingrad update. Normaly the scenario updates bring more variation of trucks for example or new units because the varity of units keeps growing.
I reworked after testplay a number of scenarios out of the 1939-1945 German Campaign. I started with Poland and Stalingrad is just finished. So yes, if you started this Campaign a while ago I think it's worth playing it again from the beginning.
If a new update is launched, take a look whats is in it. If you look at the unit graphics you will have a good impression what is added. Changes (improvements) of the scenarios will keep coming with future updates to keep improving the MOD. Greetings PHCAS