We used to try to make user interfaces "discoverable" and the essentials of their use self-evidently obvious. Now, it appears to all be about "user experience", and actually making the software usable for all, for actually doing things, appears to have taken a back seat to superficial appearance above all else. GNOME is not alone in this respect, but it's the worst offender. Unity and Windows 8 are also bad in this respect. Outright hiding functionality unless you know the secret on-screen location or magic keypress to activate it is not discoverable or helpful, even if it looks "pretty" or "reduces clutter". (Unity hiding application menus is another massive failure.) If you need a 10 minute introduction to explain how to use it at the most basic level, like how to start an application (or even find out what/where they are) and how to switch off your computer, then it's quite clearly fundamentally broken.
And it's not like the problems are just skin deep. There's a lot more to a desktop environment than the surface appearance alone. It needs quality, well-maintained libraries underneath that. And the GNOME libraries are a poorly-maintained, buggy pile, which were always changing too fast for comfort, but at least didn't used to have core functionality ripped out on a whim. Any developer who values their time and the quality of their code would avoid them.