3.0 doesn't really change the interface. But there's a good third party overhaul called PhotoGIMP that changes it quite a bit and makes it pretty nice to use.

There's also a plugin called Resynthesizer that adds in the ability to do content aware fill, and the G'mic plugin, which adds hundreds of interesting effects and tools (works with many applications, such as GIMP, Krita, AffinityPhoto, Paint.net, etc)

I did - in fact I have it installed, alongside 2.10. It's better (and non-destructive edition is a godsend!), but it's still clunky to use. I'll give you some examples of what I mean:

• The Filters menu is a mess. Where do you reduce noise - in the Noise submenu? (Enhance) Where do you apply the Old Photo effect - in the Artistic one? (Effects) If you know the name of the filter you'll probably find where it is by guesswork, and if you don't... there's no picture whatsoever to help you out.
• Why the hell is Resynthesizer not automatically installed??? It's such an amazing tool, but hidden from most users!
• As you edit text, you can change attributes (font, size, colour, etc.) either in the left panel (before adding the text) or the floating pop-up (in-text edition). Why weren't they merged already? Just so dumb muscle memory makes you lose your time?
• You want to rotate a brush. Fine, fine - duplicate It, edit it. But now if you want to access your new brush, you need to turn all filters off, since it won't be tagged "Basic" or "Fun" or whatever.
• If you use multiple tools grouped together (e.g. colour picker and measure; or smudge, sharpen, burn), the left panel becomes a clickfest.

And so goes on. Mind you those are examples - GIMP is full of counter-intuitive, counter-productive stuff like this. (I still have a mad respect for the creators of this mess, though; even with all those papercuts and annoyances, the software is functional, and a great piece of libre software. But it's clunky.)