I don't see the point, honestly--as long as the design is reasonably clean, and everything works properly, I just don't see any need for user-selectable themes (with the possible exception of things for accessibility--font size, high contrast, etc.). But that's just me. If you have a suggestion for the devs, file a bug report--discussion here isn't going to get the devs' attention.
The reason for the new UI is very simple.
The old UI is very dated and highly unintuitive .
You have two different menus with often duplicate function and for new users its a confused mess.
It lacks information and customizability which in this day and age there no excuse for...hell you can't even see simple system temps without doing some hacking of your own.
There are of course other things like the colors..seriously whats with the windows 8 metro Mattel colors which no one except five year olds like?
As to why people are filing bug reports its very simple the bug report system is a bigger more out of control mess then the new UI.
Anyone can edit the section with no grace period, there is duplication that often gets combined together with other reports creating a cluster..bleep.
Other times information is lost for the very same reason which slows progress far beyond what it should be.
Slowing it down, putting in a grace period before anyone can change things, put even a small degree of control into place would vastly increase flow and lead to quicker resolution of issues.
Us as consumers who have looked into the business end have walked away for this very reason most of the time since who wants this mess behind your development of fixes.
Our company spent near 30k in a storage which we upgrade last month.
It wasn't with TrueNAS among other solution which we looked at with a group of five people and when we came back and compared the issues with TrueNAS looked like we had all copied the same paper. The issues were so glaring and obvious every single person saw them and wondered how things can be left like this in a business.
Finally you get to big issues .
One is the behavior in the forums of late with mods going after people complaining or commenting.
As long as those people don't attack others or use foul language leave them be as it lets of stream and often leads to better ideas for development.
Don't pull this hard handed nonsense that there been so much talk about since these people are the ones who make it popular and this in turn effects how popular truen-ass is.
Or in other words don't pull a boxeebox and tick of the user base if there entirely no need for it.
Second there is a play of ego involved in the development of FreeNAS 11 which is causing the UI development issue among other ones.
In business it common sense to take what works and drop what doesn't.
The Corral UI was actually something that worked quite well and was quite intuitive to use which even gave you some customizability on the desktop for desired info.
But because there was a battle of egos between the guys who wanted to keep going with the legacy code and the Corral team so what worked great in Corral likely wont ever see the light of day in FreeNAS 11.
This makes no sense for people running a business and doesn't really inspire confidence.
Ohh yes this is a open source and free which people should be grateful for but let's not forget that this is also feeding development for the business end.
Ideas and new functions are tested here before they ever see the sales end of things and frankly that does make good business sense.
So in the end its a happy marriage and not nearly as one sided as some would like to point out.
Last if people are behaving and just questioning or venting politely leave them be.
If you don't agree then politely respond like others have and if you can't then don't bother posting.
They are not causing harm and when you go after them for posting or outright attacking them you do end up causing harm to development.
Because the longer this new trend in the forums keeps going on the less popular with people leaving for better options, which in the long run will end up hurting the open source development and eventually the business end.
There is much needed change needed for the future of FreeNAS and the outdated UI is just a obvious example.