The First Main thing I want to have in issue tracking system - is simple and clear process of creating new issues, and possibility to track them.
By forced implementing of new dumb design you deprived customers of:
1) Creating New Issue in 'New Page' (mouse2->Open in new page)
2) Creating New Issues in full screen mode.
3) Track their issues - right after customer press 'Create' - frame with new issue disappears, and that's all - customer have to use search or filter, to find issue, which just been created.
That's all - I even don't mentioned on other eyeballs out design and functionality...
How could system been rolled back to classic view?