Wouldn't the Sequels be Better If...
... They followed the boy (Pinky) growing up? I never understood why humans disappeared from the sequels, and imo the sequels went far downhill. If they did include humans, the sequels could have gone as follows:
2. Pinky is a kid (8-10 years old). He spends more time with animals than people and tries to understand them. He could communicate via interpretive dance and drawings. He would go looking for the original gang (Sid, Manny, Diego) and recognize the necklace his father gave Manny. Sid would probably end up being a "translator" by exchanging interpretive dance routines. Manny could still find and fall in love with Ellie (but maybe drop the whole thinking she's a possum thing)
3. Pinky is an adult and leads his own tribe (including a girlfriend), living closely with animals. He can now communicate with people and animals equally. Peaches could be a kid by now. Diego could find Shira (but drop the world coming apart plot). Maybe add in the dinosaur plot because Buck is awesome.
4. Original gang is older now and looking fondly upon their descendants, multiple species living and working/playing together. Something else would have to happen to shake things up, however. Maybe the flood?
Also, cut down on Scrat scenes. What do y'all think? (I really don't know what made me decide to plan these out, lol)