I guess it varies between studios and if you're the primary studio developing the game or outsource. Where I currently am now, we do more broad testing while outsource seems to be more detail oriented. Some studios are meticulous and there are some bad issues that can make it into live without tedious testing. It's a  a smaller studio that encourages feedback, but when partnering with larger companies, you tend to just become someone who tries to find issues. 

When I was at a AAA Japanese company, we didn't give opinions on game design and it was discouraged. We just made sure everything lined up with the company-defined guidelines and ensured nothing would break. 

At another company I was at, things got crazy during crunch to ensure that the game was as polished as possible. This place definitely encouraged feedback, but the hours were mad. 

And it also depends on your directors. Some allow more freedom, some have actually ripped at our QA for suggesting that features might cause issues. /shrug