Not everything actually requires a GUI, obviously. But anything that requires configuration, especially for controlling a hardware device, should have a fully functional GUI. I know Linux is all about being in control, and users should not be afraid to use the command line, but if you have to learn another bespoke command syntax and the location and structure of the related configuration files just to get something basic to work then the developer has frankly half arsed it. Developers need to provide GUI's so that their software can be used by as many people as possible. GUI's use a common language that everyone understands (is something on or off, what numeric values are allowed, what do the options mean).
Every 12 to 18 months I make an effort to switch to Linux. Right now I'm using Archlinux, and it has been a successful trip so far, except my audio is screwed, I can't use my capture card at all, I had issues with my dual displays at the start, and the is no easy way to configure my AMD graphics card for over clocking or well anything basic at all.
I'm not looking for a windows clone, I love that I can choose different desktop environments and theme many of them to death. I even like the fact there are so many distros. Choice is a big part of linux, but there is clearly a desire to get more people moving away from Windows and until that path is 95% seamless most people just won't. Right now I think Linux is 75% to 85% seamless depending on the use case and distro but adding more GUI front ends would, imho, push that well into the 90% zone.
GUI is not a dirty word, it is what makes using a new OS possible for more people.
EDIT: Good conversation all. This is genuinely not intended to be a troll post, I just feel it is good to share experiences especially on the frustations that arise from move between OSes.
I guess you're not an opensource developer. Let me put it in terms that you understand:
Let's say you're a pizza delivery dude. You have to be out every day, delivering people to rude customers, no matter the weather. It's hot and your balls are sweating off, if cold and your fingers are freezing, there torrential rain and you get soaked for every delivery, but bossman don't care - you have to do it!
To relax, you have a hobby as a wood worker. It's your passion! You make small things to make life a little easier or things that look cool to you.
One day, you buy a cupboard that's been all the rage. Every store out there has it and it's flying off the shelves. But after a few months there's something annoying about the way it works. Not a problem for you, the handyman, the woodworker. It takes a few weeks, but you've designed, built, and tested a few solutions to arrive at something that works. It's not beautiful, it's not trendy, sexy or anything, it just works.
Thinking to yourself "hey somebody else might find this useful", you put the designs online. To your delight, there are a few people using it. Very few "thank you"s, but that's fine, at least it helped somebody.
Then one day, some dude writes a comment about your solution titled "Build something beautiful or GTFO".
Tell me, how would that make you, as the hobby wood worker feel?
I get it. I'm not a pro developer but I code quite regularly. I realise all the support you need to give for anything you develop, the time and effort involved. And frontends often take more time build than the thing it presents. My point is, there are basic gaps that need should have been addressed by now. the KDE and gnome devs could focus on those items rather than the next impressive theming function.