Bugs faced after moving to Gnome 3.12 on Xubuntu 14.04

One of the major issues I felt in Gnome was the extensions installed get disabled after restart (since I can't go to sleep anyway). The fix suggested was to use the "System default".

 It didn't fix other issues like the sleep mode not waking up and the classic mode not showing any elements, but I am tackling issues one at the time.
Message tray pop ups
message tray, it looked big and annoying ( it responds to every mouse gesture no matter how small)
It's also very big in size, it took 5GB more than XFCE took, even with cleaners like Bleachbit, I was running low on space.
No sleep
I didn't even know how to go into sleep mode, turns out you need to press and hold ALT while the menu is popped out to go to sleep menu.
Doesn't wake up from sleep
I couldn't find an explanation for this bug! The computer displays a black screen whenever waking from standby and stays that way until I turn it off manually!
No classic mode (just a background)
It only loads a mouse cursor and a background with no visual elements until I turn it off manually! No easy fix or workaround for it (yet).
Extensions won't install
I wasn't able to install extensions from the extension site, extensions.gnome.org even after enabling the addon in my browser and adding the site to trust list. It was resolved on it's on.
After install won't stay enabled after reboot
Even the extension that is supposed to make it less sensitive resets on reboot. The fix was to choose the “System default” from the login which (worked for me like many other people). It wasn't convenient but it was an easy fix.

 I'll post that has a fix for most of these issues very soon :)