I hear all the wrong reasons to remove the feature, so let me give all the reasons why it worked before, why it was never an issue and why the current "Edit a config file manually" approach is wrong:
1) Absolute most people don't use the VM shutdown feature. They press "Start -> Shutdown" in whatever guest OS they are using instead. Using a VM shutdown dialog in just not as convenient.
2) The checkbox is in your face. It's not hidden, it's right there and it's hard not to notice it. People who were burnt by pressing it accidentally maybe did it once in their entire life. I cannot imagine making this mistake more than once.
3) Now instead of a UI feature, I need to edit a config file and then remember the discard feature is enabled. WTF? What if I use it the feature intermittently? I.e. I need it today but I don't need it tomorrow? Go edit the config file again and again? Really??
4) It literally takes a couple of lines of code to hide it by default from all the users and have it enabled only for those who want to use it.
Now, whenever I want to discard the last state of a guest, I need to switch it off, go to snapshot management and hit all the right buttons (an extra ten buttons if you had your guest on any other mode, e.g. Details vs Spapshot management). Multiple actions which were available as a single click of a mouse earlier.
Your UI team is doing all the wrong stuff it seams.
Here's what you could have done instead:
viewtopic.php?f=15&t=106906 - not a single comment from anyone on the team, meanwhile the guest menu is a total incomprehensible illogical mess.
Also the main actions switcher under the main menu (Welcome, Extensions, Media, etc) terribly sucks.
Also the guest actions pop-up menu is terribly inconvenient (Details, Snapshot, Logs, Activity, File Manager). Why is it hidden by default BTW? Why it's only visible on mouse hover on?
People have 1080p, 1440p, dual monitors configurations - you cram everything such a way you need to constantly mouse click, click, click.
The guest actions are all easy to show on the screen simultaneously or make them some sort of tabs. A single click to switch between tabs.
Likewise for the the main actions switcher - why, why, there's a drop-down menu where there's so much space on the screen? VBox is a desktop application and it now looks like the worst UI-wise mobile app.
I presume you have designers/managers on your team who have to make stuff up to get salaries and in the end we get a horrible usability-wise UI where you need to click often while making sure your mouse movements are precise. This is nightmare.
UI in VBox 5 was a
ton more easier, faster and more effective to navigate.
VBox 7 is the absolute worst in terms of UI (I started using VBox around version 3 I guess) and of course user input is not necessary because "managers" and "designers". Have these people formally run any usability tests? I doubt it. Something was designed as "cool" and "modern" and poor programmers bent under because they had no choice.
Of course this salty rational logical message will never reach the responsible people. Not the first time. The PC software industry has done everything to destroy usability over the past 15 years, starting with an abomination called Windows 8.