I fail to see how your OO approach is any better; all it does is wrap some global variables inside a class.

That is how its better, its called encapsulation

You can have $foo and $bar both be of type Classname, with both being able to ->dance and ->sign

Its better in the same way subroutines are better than not subroutines ( goto )

Its also why  Main(@ARGV); sub Main { } is better than  MAIN: { } because you can only  goto MAIN , its a label, its not a subroutine, you can't call it

Its better in that its : testable/mockable, reusable, not fragile Action at a distance (computer programming)

http://programmers.stackexchange.com/questions/148108/why-is-global-state-so-evil

You cannot have more than one instance of global state -- its global

Also, it's silly to store multiple blogs (with identical schemas, I presume?) across multiple databases.

So is everything you wrote :)