I installed the season pack addon (Fall N. & Spring S. by Bijan Habshi) last week. It was added for this WU. Took me an age to get Belgium to load without crashing. I had to fly in from France to make the cache update.
So no, even with the market place there can be issues. Add in that one add on could counter another add on. The variables to check this out across all locations would be too much to expect.