It seems there's always a lot of hate for Taz & Tenay, but I (for one, maybe the only one - lol) like them as the announce team for TNA/IW. I thought it was really weird seeing JB and that guy I'd never heard of, or seen before at the top of Impact. Thank God they put JB with him, and we didn't have two no-names announcing the show at first.
When Impact first started, I think it was JB who said "Taz & Tenay will be joining us for the second hour of Impact" (or something to that effect). After hearing that, I honestly thought he meant that there was going to be a FOUR PERSON ANNOUNCE TEAM on Impact for the 9 to 10pm hour. I was very happy that JB and the other dude (don't know his name, and too lazy to find it) left when Taz & Tenay were ready to take over. One thing that really bugged me though was the moment when Taz & Tenay took over the announce table; it seemed really awkward that when Impact came back from break, we saw Taz & Tenay at the announce table - and JB & the other dude standing behind them. It was also very awkward to watch JB & the other dude take their headsets off, shake hands with Taz & Tenay (Taz made the "handshakes" very awkward as well), and then leave. The whole thing just seemed really unprofessional to me, and it should have been handled better. Maybe JB & the other dude could have said "goodbye" to the audience before the commercial break, and said that Taz & Tenay would be taking over when Impact came back from the break. That way we wouldn't have had to see all four of them at once, and Taz & Tenay could have still congratulated the first announce team without them having to be there. WCW used to switch announcers half-way through the show as well, but they did it during the commercial breaks (if I'm not mistaken, Bobby "the Brain" used to replace Tenay for at least the last hour of Nitro in the late 90s).
One of the thoughts I had when I saw the "new" announce team (JB & "the other dude") was that maybe TNA was testing these two out because they're thinking about adding another TNA show for TV (kind of like their version of "Smackdown", or whatever). I know TNA also has "Xplosion" (if I spelled it right), but that doesn't air in the USA. If TNA/IW was thinking about putting a new show on North American TV, they'd probably want a different announce team for the show. I'm not saying that TNA is definitely adding a show, nor am I saying that they even should start running another show...just that the possibility popped into my head when I saw them testing the water with a "new" announcer/announce team.
It might have just been something simple too, like Taz and/or Tenay got to the Impact Zone late (and needed a last-minute replacement), or it could have simply been that they wanted to give this new guy some experience so he could be used as a backup if an emergency were to ever come up for Taz or Tenay (or even JB). It's never a bad idea to give someone a shot at the announce desk (like TNA gave the "new guy" the other night). If Taz and/or Tenay are unable to announce for an episode of Impact (or a PPV or whatever) it's great for TNA to have someone other than JB they could throw in that position as a backup (that's had actual TV experience as well).
To be perfectly honest, the announce team for the first hour didn't seem to change the dynamic(s) of Impact at all for me. It was a little weird at first to hear the "new guy"s voice instead of Tenay's (as the play-by-play guy), but I got used to it part-way through the first match on Impact. When Taz & Tenay came out for hour #2, I hardly noticed a difference at all. I guess Impact is Impact, as long as someone is announcing. After all, JB & the other dude pretty much said whatever lines they would have fed to Taz & Tenay anyway (I'd imagine neither one of them is ad-libbing very much). I don't think that Impact's TV producers try to give their announcers their own "personalities" or anything like that; they just have a play-by-play guy and a color guy. I'd have to imagine that most of their lines are scripted, and the first announce team just read what would have been given to Taz & Tenay regardless.