The Cena match is one that I think actually worked. I always forget that Cena won, just the absolute beating he took for the entire match and being cut open is all I remember. Then again, Cena had to win - forget who the Champion is, Cena is the guy that headlines virtually everything in WWE - if Lesnar just comes straight in and beats him, it could be argued that there's no-one else who could have beat him at the time. Weirdly, now Lesnar has to win the Summerslam meeting, otherwise WWE is basically saying that Cena could have ended the Streak - but they were kept apart.
The Triple H matches shouldn't have run to three, the Punk match at Summerslam was a blinder, the Taker match wasn't all that great until the finish. However, I do think he's been worth it, for one match:
vs Big Show, at the Royal Rumble.
The two second non-match where he just killed Show with chairs. In the build-up to this, he took some huge bumps, and in two episodes of Raw, made Show look like a monster with his selling and retreating. Lesnar is selling like a dream for other guys, something that is a lost art in WWE. He then got himself back over as a monster by pretty much slaughtering him with chairs, and Big Show by hobbling out afterwards rather than doing a stretcher job made himself look really decent too.
If you watch, Lesnar shows weakness, sells, and does what he can to make the other guy look as strong as possible. He made Punk look awesome in their match, and only survived on Heyman's interference. The only time I've disagreed with his booking was the build-up to the Taker match, but in retrospect, that was to make the end of the Streak even more surprising.
The way he's willing to show weakness when in reality he'd be able to kill the entire WWE roster is something pretty much every other headliner in WWE could learn. Imagine if Cena was willing to do the same...