They (EA) seemed to prefer to work on stuff packs and the extension packs they sold separately instead of fixing the bugs and glitches in the new stuff and extension packs. You had to go through some changes to get them to work with previous mods, usually uninstall then reinstall the new ones to work with the expansion and stuff packs.
I know that when I had Sims 3 installed and EA (Entertainment Arts) had glitches it was usually the mod developers who fixed most of them. How do they work in upgrades? Do you have to have the mods, does it affect the game if you don't? I've never had mods on my computer games.