This is the problem with being a small business that gets too successful, too quickly: everyone expects the service of the big guys.
Terraria was what, $9.95? And I'm willing to bet that every single person who purchased and played it probably put in a LOT more time than games that cost 5x that amount.
Were there bugs? Absolutely, but show me a game that doesn't have them. Most of that subforum Rob mentions are feature requests and new things that people want added (for instance, "I don't want to host my own game, I want dedicated servers). These things are not small version changes in the code and they're not bugfixes, they're feature additions. Andrew handled bugfixes for the game in an incredibly timely manner for a one-man coding machine.
It's just a shame that there's so much wailing and gnashing of teeth about a person deciding (sensibly) to move on. He's even promising that there will be one more solid bugfix patch, which means Terraria will have a year of active support after its release - shit, even EA doesn't do that most of the time.
Indie game development is about the developer's vision - Terraria reached what he wanted it to be. If we want to encourage him and more people like him to develop great games, we need to be respectful of the creative process and not expect and demand things we didn't pay for to begin with. Otherwise, I feel like we're just as soul-less on the consumer end as they are on the big-publisher end that we all bitch about.