DivinylsFan Sorry for the late reply; I'm having trouble keeping up with the forums lately.
To answer your questions, if you still have them:
- The entire game minus Store content takes up about 32 GB
- This amount of data is completely fine to install on any computer that will have more than, say, 40 GB free once the game is present: another 10-15 GB for saves and other data leaves 25-30 free, which is really all you need
- .NET Framework 3.5 is a runtime Microsoft produced for applications to use and is not a "scam" in any way, plus Sims 3 won't open without it