Why not use the native (unity) shortcuts:
ALT middleclick - resize window
ALT leftclick - move window
I never knew the middleclick thing. 😉
The last 2 versions of O25 has a better integration with Unity (with Unity menus). An you don't need this command parameter anymore. Resize handle is working out-of-the-box.
There is an experimental build Opera 25 developer which is available for debian-based systems (Debian, Ubuntu, etc.) ... but of course that's the Chromium-based version. The last Presto-based version was/is 12.16.
The chance to see that fixed in Presto-Opera is probably pretty low. Currently there is Opera 25 Developer for Linux. I guess it could reach stable in 2-3 months.
A maximized window cannot be dragged in most window managers.
The area above the tabs where you can click to drag or double-click to restore is pretty narrow - people who want to run Opera maximized prefer it that way so the tabs go all the way to the top of the screen. Since you don't appear to want to run Opera maximized, you could go to opera:config and set "Chrome Integration Drag Area Maximized" to a larger number (at least 5) to make it easier to find the right area.
Inappropriate - that is, not related to Opera or Linux. Try a web design forum. And if you post another link to your site, you will be banned as a spammer.