To be honest, I think almost everyone who designs professionally thinks that. If you didn’t think that, you wouldn’t design, because there are so many other designers out there, so you must have a certain amount of hubris to attempt it.
Full disclosure: this includes me. Most of the designers I’ve met, I’ve felt were idiots. Mostly seat-of-the-pants types who don’t think through anything they add to a game, they just add it because it sounds good. They’re often innumerate as well. There are exceptions, of course, like Chris Taylor (Fallout’s Chris Taylor, I’ve never met the Gas Powered Games Chris Taylor).
That doesn’t mean, by the way, that I am particularly good at it. I think I did a decent enough job with the combat systems in MAX, but when I think about Heroes IV, I wince. It had a host of serious design problems, not just implementation issues from being rushed out the door unfinished. The Russian versions of King’s Bounty (KB: The Legend, Armored Princess, etc.) do just about everything I was trying for, and do it about 5x better.
Oddly, this is also true. It’s a weird dynamic of the games industry, but it’s something I’ve observed first hand, where people get promoted from QA to designer even when they aren’t half as good at design as some of the programmers on the team.
So, I was expecting to read something objectionable in those two links, and I didn’t. Whatever you may think of Garriott as a designer, he’s not wrong. I’m sorry you feel he was denigrating “today’s” designers, but he was talking about real problems with every generation of designers, past and present, not just today’s.