Whether its Brock, Taker or The Rock, if you can't commit to the WWE full time then you don't deserve to have the belt.
The person the company decides deserves the belt, deserves the belt. Brock only has to "commit" to the number of dates the company offered him to be contracted for. Remember, they decided they needed him FAR more than he needed them, hence huge money for limited dates. If WWE think they can pop a big buyrate off a huge Lesnar title defence with a couple of month build where he isn't necessarily on TV every week, then he deserves to have the belt. That's the gamble.
It's not fair for the fans who are champ-less for half the time, and it's not fair to the non-champs who could make better use of a title run.
The fans argument is bullshit. You watch the wrestling for the wrestlers and the matches, the belt is just a prop. If you don't want to watch the exact same roster that the shows have been built around, minus Brock, for the vast majority of the year just because one of them isn't waving a belt around, then what does that say about the roster? It's piss weak and you need the belt to be waved around every week on Raw for anything to matter? Besides, half the fans that go to the house shows every year go to shows run without the champion present. It's an ensemble piece, you go to see "WWE" not just "the WWE Champion."
I'd much rather have Lesnar be absent for a while and have a couple of months where they establish who the next challenger is with a really strong build so when the match comes around it feels giant and there's a bigger sense of anticipation. That's why Lesnar is such a big deal - he
isn't around all that much, so it's a huge fucking deal EVERY time he steps in the ring. SummerSlam was a giant deal because of using Lesnar in the way they did, and they were able to build a card that had an almost WrestleMania like feel to it. If part-time Lesnar having the belt means we get another match with that kind of feel/build to it between now and New Year, I'm happy. Truth be told, they could have shows without the title contested for a few months and they'd only be as missable as Money In The Bank or Battleground were in my eyes - two shows I passed on because the result of their main events were fucking obvious so there was no suspense, even with the bloody title contested.
As for other people making "better use of a title run" - like who? The other guys that might be in that position right now are either over-exposed to fuck or not ready, apart from the injured Daniel Bryan. The person that will get the best use out of a title run is the guy the people will pay to see, and after he barbecued John Cena, that guy is Brock Lesnar.
It's like giving an executive parking spot and corner office to an employee who only comes into work once a month.
Only if the wrestler in question is a massive fucking mark. Lesnar only cares about the money, he couldn't give a shit really about being the champion or if he wins or loses. If that mattered to him, he wouldn't have acquiesced to losing a fight to Cena in his first match back or losing to the virtually-retired Triple H at Mania 29. He's not a mark. Giving the belt to Lesnar is not a reward for anything he's done, it's a means to an end to get maximum return on their investment. They think that more people will pay to see a PPV with Brock Lesnar involved if he's on top and fighting for the title. I think they're right.
Not appropos of Lesnar, but they will care less and less about what's happening on the PPVs on a month by month basis, as long as they've nailed their 6 month Network renewals every time. Given the time the renewals are coming around, SummerSlam being almost as big a deal as Mania with the part time megastars or returns and matches with longer term build is likely to be a permanent thing. I welcome it, since most of the last 5 years or longer, I've rarely given a shit about anything that's happened between Mania and the next Rumble.