A few things to point out here.
For one, people get very nostalgic about what 'was so great about wrestling in the past' and easily forget how much in between the 'great times' there was a lot of VERY MEDIOCRE and bad stuff there was that they forget to mention.
The Oddities were on Raw about the same time The Rock, Stone Cold and DX were running wild. The Oddities were a bunch of misfits put in joke matches. People complain about The Great Khali, Slator Gator, Adam Rose and The Bunny but are they forgetting there were pointless joke characters and matches back in the beloved Attitude Era? Probably.
The brings up the second point. What is "Must-See TV"? Well, I'd say it's TV that makes you want to tell somebody about it and say "OMG, did you see what happened last night?" or just say to yourself "OMG that was crazy! or cool!" So some might say something like Steve Austin bringing a beer truck into the arena and spraying down The Rock and The Corporation. Ok, fine. But when did that happen? IIRC that happened the Raw before WRESTLEMANIA! How many times did it happen before that? NONE that I know of. So, this big huge 'must-see' moment happened the week before the BIG SHOW. Yes, it was great. But it wasn't like it was happening every week. Sure, Austin usually was doing something hardcore and renegade each week but it wasn't as elaborate as a beer truck so people have to realize it can't always be huge things happening every week.
Sometimes I think people have to give WWE a bit of a break because they are pumping out enormous amounts of new content each week. I say "a bit" of a break because a the WWE does bring it on themselves. Like, do they really need a 3rd hour of Raw? They couldn't even get their US champion on the Raw after NoC yet they made time for TWO Divas matches AND a promo? So I still think they could be smarter with their time, but on the other hand, they can't be expected to put out ground breaking episodes every single week.
Just like any of you who watch late night TV. Those shows are the closest to the WWE in terms of their demand for new content. They do have a longer 'off-season' but when they are on they are trying to pump out an new hour of TV for 4 or 5 days of the week. And guess what? Not every episode is good. A lot of them actually suck. Doesn't matter how charismatic or funny the host is or how good one segment may be. If the bulk of the show felt 'bleh' then the episode gets an overall bad rating. That's the same challenge WWE has.
So, to get more to the point at hand:
What exactly is "Must-See TV" for wrestling and what examples of it are there in the current product today?
- Hardcore matches/segments. I know they don't happen often and are called "No DQ" or "Falls Count Anywhere" matches or something else but anytime they happen it is fun to watch. Dolph Ziggler vs Sandow in that "Hamptons Match" or some other match with a bunch of instruments a while back was fun to watch because it was different and fun chaos. Some of my favorite stuff from the Attitude Era was The Rock vs Mankind in an Empty Arena and Stone Cold brawling Booker T in a supermarket. Just fun to watch. If WWE could do something even CLOSE to that these days they could see the positive response.
- Dean Ambrose. He is an intriguing character. He does things against the grain and that's fun to watch. The stuff he did distracting Rollins at ring side with the soda, popcorn and hat in the briefcase is stuff that makes a Pro Wrestling show FUN to watch. To me, on Pro Wrestling shows I like to watch stuff that would be fun to do but you don't really get to do in real life. That's why Dean is popular and gets Austin comparisons because Austin was interesting in his time because he went against the grain and you never knew what he was going to do next.
- Title Tournaments & Challenges. I love when the titles are the focus of a show. I love when there is a tournament to be the #1 Contender for a title or even a Battle Royal or a Qualifying Match for a spot IN a title match. Anything that makes Pro Wrestling more SPORTS-LIKE than just "entertainment." Because to me, that's why Sports are popular. When you get to playoffs people love to see the best of the best battle it out down to a single spot. WWE needs more of that, and when it happens, it is good TV.
- Unique matches. Yes, a good one on one traditional match can be GREAT but I love a match where it is different from what you normally see if you flip to a boxing or UFC match. Stuff like a 6 Pack Challenge Elimination Match or a Triple Threat Tornado Tag Team match or a Ladder match make TV "Must-See".
- New rivalries/matches. Surprise to hear that we aren't going to be that excited about John Cena vs Randy Orton for the millionth time? Well we aren't. How about Randy Orton vs Ryback (a face and built up to look STRONG Ryback)? Or Cesaro vs John Cena where Cena loses clean AND THEN shakes Cesaro's hand? Or Tyson Kidd vs Daniel Bryan when he has returned and the match goes 15 minutes to show how both competitors are good? NEW rivalries and matches we haven't seen very often make it must-see!
Basically my answers to the first question answer the second question as well because the stuff I said are things WWE have done in the past but not as much as I would like. There isn't really anything I can think of that WWE has never done that I think they could do to make it 'must-see' TV.