Hera Pheri comes from a time when we were not used to this kind of a humour. After a complete decade of mindless slapsticks by Govinda, this seemed like something that was completely driven by the comic timing, phenomenal acting, the setting and the story. If any of these elements was missing this film would have also crumbled down like the later comedy movies of Akshay Kumar. What exactly makes this film special are the characters, their relatable behaviour and the situation they got in.
Raju, Shyam and Baburao have now become household names. The character of Kabira has also become something staple with bad guys on phones. Amrish Puri chasing Shyam for returning his money so that he could have his sister's wedding was a very well done runnig joke. And finally the ending scene was also very satisfying. Overall there was a great performance by all the actors.
I think I have heard this movie is going to get a third part with John Abraham. I'd absolutely not want that. Replacing Akshay Kumar with John Abraham will surely ruin the franchise (like Welcome and Welcome Back). I'd prefer that both of them should stay, if the planned sequel is actually very good. But otherwise a duology is perfect.