1. No one knows why EA does anything. Because they suck.
2. Since it was done by design it can't be "fixed" so much as worked around. Awesome mod at MATY gives you the option to switch houses, however the families you leave will still progress. With awesome mod you can make your favorite families "sacred" but that only stops major events from happening while you're with another family--they will still go on living while you're away and can still die of old age. Still it's a major improvement on game play options by Pescado.
Be aware that many mods for EA fixes are still in Beta form.
3. No, we all were all disappointed in the single house play when it first came out.
4. No, EA could care less about changing things once they have your money.
Really there is a lot of information out there on how to fix many Sims 3 issues, so be prepared to search the threads and read up on all the progress. Have fun

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