Brock doesn't need the title to get over, but having it carried by Punk, Bryan, Sheamus, Ziggler, Rhodes right now is helping.
Brock, Rock, Undertaker, HHH, Cena (in all honesty) don't need titles to headline PPV's. A lot of folks are decrying how "unimportant" the WWE/WHC titles have become, but wrestling has had these kinds of characters since it became national (rather than regional, when a guy had to carry a belt because he wasn't immediately known to the people in every town; a championship was necessary for "Charlie Brown from Outta Town" to get immediately recognized as a badass). In his WCW run, Hogan didn't need to be world champ (even though he was), because everybody knew who Hogan was and respected him even though he wasn't the champ.
Since then, it's like there are four "divisions" for single, men's performers (or five if you have Cruiserweight/Light Heavyweight): the lower card (which doesn't have a title, and partisans of the IC/US titles don't want to see "their" belt lose prestige to become the lower-card/tertiary title, which is what the WCW Television and WWE European Titles used to be), the mid-card (who compete for the IC and US Titles), the main-event/mid-card/upper mid-card (who competes for the WWE and WHC titles), and the "permanent" main event (guys who are always going to be over and known regardless of whether or not they're carrying a belt.
Brock is, for better or worse, in that last group and has no need to be WWE Champion.
Unless, that is, they want to elevate one of those upper mid-card guys to the "permanent" main event. If you had Brock become WWE Champion (this is what an earlier poster basically said, too, by the way), just to lose the WWE Championship to CM Punk (for example), it should push that performer into the "permanent" main event. (BTW, I don't know if Punk would be the guy; prior to Orton's latest suspension, I would have put him in the role of the guy that beats Brock to get elevated, but I don't know how said suspension affects WWE's view of him....and, no, for the people who just screamed at me, Randy is not quite part of the "permanent" main event yet, although I would have sworn he would be soon before the latest suspension; he and Punk are both in the upper echelon of the upper mid-card).
At least that's how I'm seeing things right now.
wk