The iPad 2 and 3 have older processors. Ensure no other apps are running in the background and that your Wi-Fi signal is strong. Alternative: Use the Safari Browser
Even if you install a raw .ipa file via a sideloading tool, the app will often crash because it isn't "signed" by your specific Apple ID. netflix for ios 9.3 5 download link
Netflix sometimes retires very old versions of their app for security reasons. If the app opens but gives a "Connection Error," the servers for that specific version may have been decommissioned. The iPad 2 and 3 have older processors
Search for Netflix in your list of previous downloads. netflix for ios 9.3 5 download link
Ensure you are signed into the exact same iCloud/App Store account on both the new and old devices.