CI 2.0 router function set_directory

[eluser]searain[/eluser]
In CodeIgniter 1.7.2

Code:

function set_directory($dir)
    {
        $this->directory = $dir.'/';
    }

CI 2.0

Code:

function set_directory($dir)
    {
        $this->directory = str_replace(array('/', '.'), '', $dir).'/';
    }

So in CI 1.7.2, I can call set_directory() to set up multiple levels nested controllers subfolders. But in CI 2.0, it seems that it specifically replace the '/', don't allow I use set_directory() to set up multiple levels nested controllers subfolders/

What is the logic that CI 2.0 use

Code:

function set_directory($dir)
    {
        $this->directory = str_replace(array('/', '.'), '', $dir).'/';
    }

Instead of

Code:

function set_directory($dir)
    {
        $this->directory = $dir.'/';
    }

If I override the

Code:

function set_directory($dir)
    {
        $this->directory = str_replace(array('/', '.'), '', $dir).'/';
    }

replace it with old

Code:

function set_directory($dir)
    {
        $this->directory = $dir.'/';
    }

What would be the consequence?

CI make this change for a reason and I don't want to override it back to old codes without knowing the reason.

Thanks!

[eluser]searain[/eluser]
Any advices?

Thanks!