My experience has been different. I had occasional, but not out-of-control, crashing before the update, maybe once every two hours of play or so. The frequency is unchanged since the update.
Crashing happens most often when I'm moving or placing objects. Now I also occasionally get the "green screen of doom" when visiting neighbors. Never had issues with particular characters.
I play on an iPad 2 with a strong WiFi signal, have 100 neighbors, all characters & premiums, lots of decorations, lots (but not nearly all) land.
Aside from crashing, the game is less stable for me since the update: way more texture glitches (Pimento grove almost all the time), rampant moonwalking, occasional other glitches - brown houses turned into Kwik-E-Marts, quest count of -24/1 for Bart, about a quarter of my buildings disappeared once - but these all corrected themselves if I closed out and restarted the game.
Overall, I can't complain. People's experiences with the game seem so uneven, it's hard to come up with a convincing theory about what does or doesn't cause crashing and other problems.