Alternatives

In my opinion, I really don't see a necessity to kill mysql extension. If It's Not Broken, Don't Fix It!

To those developers who use databse wrapper class, like myself, it shouldn't be hard to migrate to other extension (simply rewrite class to new extension with same interface), that's the beauty of OOP.

But what alternative it's better to use?

The idea behind PDO is great, crossplatform database access would allow you to use same class in virtually any PHP project. But there are plenty of little things that might not work in different database platforms, because they offer different functionality.

And using just mysqli might mean, that someday in the future we might face same problem, when they'll decide to kill mysqli and force everyone to use PDO :D

For myself, I'll try the PDO way.

I think that's part of the game, new technologies replace old ones.
yes mysqli and PDO will also eventually die and new libraries with new features will take their place and I personally will use those new libraries. that, in my opinion, is a good process. it speeds up the arrival of new technologies.