Comcast (NASDAQ:CMCSA) has one of the most daunting challenges in the media industry: boosting its NBC asset. At times, NBC has been beset by prime-time difficulties, ratings concerns in its highly successful news division, public-relations woes relating to the Today show, strong competition from such time-honored competitors as ABC and CBS on one front, and programming competition from a slew of cable and other programming dynamos on the other.

NBCUniversal has had to face numerous questions. Is its plan to replace Jay Leno with Jimmy Fallon in February going to pay off or will it damage one of the most durable franchises in television annals? Can NBC fend off ABC's hard charge at 6:30 p.m. and during the breakfast hour (not to mention on Sunday mornings)? And what about its problems in prime time?

NBC's strength with the Today show, NBC Nightly News, and Meet the Press -- all of which paced the field in television ratings for many years -- enabled the Peacock Network to command robust advertising dollars.

In recent years, however, Walt Disney's ABC holding has threatened NBC's uninterrupted run of domination. The Today show in particular suffered from extended bad publicity when longtime host Matt Lauer was accused of forcing his popular sidekick Ann Curry off the show as ratings dipped. Lauer's supporters vehemently rejected such talk and he has remained with the show since then. But the downturn after the Curry exit showed how quickly even a perennially successful program can suffer in the public's eyes.

Entertainment writers obsess about such matters, but Wall Street analysts see upside potential in Comcast, despite its task of bolstering NBC. Wall Street analysts approve of the potential of Comcast to leverage its infrastructure and launch such products as home automation, media streaming, security services, and cloud storage.

In the second quarter, Comcast topped Wall Street's consensus earnings per share and EBITDA by $0.02 and $165 million, powered by favorable results at NBCU, countering difficulties at the theme parks. 

NBC's arsenal of cable properties consists of such properties as the dominant business-television channel CNBC (which has hardly had to worry much about the rivals Fox Business Network and Bloomberg Television).

But even with its strengths, NBC has plenty to be concerned about. Programming expenses have continued to rise astronomically. Such foes as AMC, HBO, and Showtime have gained currency with viewers, thanks to their daring programming choices.

Now, NBC (as well as the other traditional television networks) has another force to worry about: Netflix, whose first original-content show House of Cards, starring Kevin Spacey, earned a sizable, devoted following.

NBCUniversal appears to be capable of holding up its end. Its advertising effort experienced eye-opening growth in the second quarter, clocking in with 13% in broadcasting and about 6% in the cable networks.

But broadcasting businesses aren't Comcast's only concern with NBCUniversal. In the second quarter, Wall Street became concerned about the theme-park issue at the company, too.

Media analyst Tony Wible of Janney Capital noted in a report to Comcast shareholders: "Theme parks were weaker than expected and revenues grew only 1.3% (vs. our 12%), driven by a shift in holiday timing, but core spending trends looks good."

So, what's a shareholder supposed to make of Comcast's NBCUniversal arm? 

Its most conspicuous asset is subject to the unpredictable whims of television viewers. Meanwhile, the fortunes of its theme parks, likewise, rise and fall as the public votes with its feet.

Fool contributor Jon Friedman has no position in any stocks mentioned. The Motley Fool recommends Netflix and Walt Disney. The Motley Fool owns shares of Netflix and Walt Disney. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.