Generally speaking, as an on-air talent, there are 5 different ways to express your opinion:
1. Stick your finger in the air and see which way the wind is blowing. Be totally reactionary and simply state the obvious. Occasionally try to stir up "controversy" because that's what radio hosts are "supposed to do..." such as suggesting that the Red Sox put in a waiver claim on Manny Ramirez (Tanguay, Gary).
2. Always be "level-headed." Never express an emotional opinion. In fact, don't really express an opinion at all. When there is conflict between player and the organization, almost always choose the organization, because they're the ones who supply the interviews and are worth keeping relationships with (Arnold, Dale).
3. Develop a few talking points and keep repeating them. There's really no need to pay attention to the games or watch the games, because all you need to do is repeat your talking points. Don't let singular moments affect your talking point. Always try to make everything relate to your talking point (Mazz on Texieira...this also applies to Borges and his hate all things Patriots).
4. Supposedly offer "strong opinions," but attach so many caveats to them that you can't be held down to it if you're wrong. Yell a lot. This gives the illusion that you're really passionate about what you're saying (HEY ORDWAY).
5. Be very passionate, and stick to your guns. Don't be afraid to admit when you're wrong for an opinion. But also keep hammering your beliefs, which you do truly believe. (Felger...Moss is the perfect example of this. He had the same general opinion on Moss from 2007 onwards. Though he really "increased the Moss bashing" once 2009 rolled around and there were whispers about him quitting on the team, dogging it, etc).
Felger's thoughts on the Bruins also fall into the 5th category. He's very passionate, and genuinely believes just about everything that he's saying. If he's wrong, he'll admit that he was wrong. Felger sticks to his guns.
It's fun to listen to. Today's show was fun.
The difference between Felger on the Bruins' playoff disappointments and Mazz on Texieira is that it's evident that Felger watches the games and cares about the team. Mazz himself admitted that he didn't watch much of the Red Sox past early September. Mazz lazily chalks up these talking points. Felger is actually passionate about his. I think that's the main difference.