eZSYS::requestURI is already decoding the URL. The eZURI class does it a 2nd time.

Example of the problem. Given URL:
http://<sitedomain>/(foo)/bar%2Bbar

Double decoded version is is /(foo)/bar bar (that's a space in between)
But the correct value is /(foo)/bar+bar

You can test this by adding following into your pagelayout.tpl:
{$view_parameters|dump()}

Use following URL and look at the dump output:
http://<sitedomain>/(foo)/bar%2Bbar

The correct value is " /(foo)/bar+bar" - the pull request should produce the correct output.