Yes, I'd say Windows 10 is definitely one step down visually from Windows 7's UI. The 3D Aeroglass look in Windows 7 was beautiful. The Windows 10 2D look was done to make it easier to work on a smartphone or tablet, but nobody uses Windows smartphones or tablets, so they made it blander for no apparent reason now.
As for bugs and stuff, that's not all that much worse than Windows 7 days. Windows of any version doesn't really have a great track record for reliability. The Windows 10 forced upgrades also don't help it. I have learned a long time ago to backup my Windows stuff, regularly, so I can withstand a lot of Microsoft f*kups, and I already have actually! But it's not any worse than Windows 7's reliability.
However, Windows 7 is already End of Life, there's no further patches being done for it. So it's security is going to suffer. Windows 10's interface though visually inferior to Win7, is pretty much unchanged from Win7, so you won't have any trouble switching to it.