Mickey didn't have visions, nor Martha, or any of her family... Maybe I'm just racially insensitive, but I never pick up on this "magical nergo" stuff. I mean there's plenty of white characters with the same traits, and plenty of black people without them.
True, but that's not the point of the concept. It's just the idea in fiction of the ethnic minority character (usually black) who appears, often without explanation, to help the white protagonist, and is in some way 'special' - psychic or magical powers are jsut the sci-fi take on the idea, in regular fiction they often appear unusally wise, or in tune with nature, or in recent film, just much cooler or 'smooth talking' than everybody else. They act as plot devices to advance the tale, usually through imparting some great wisdom or prophecy which helps or serves the white main character.
A classic genre example that doesn't involve having psychic powers is Morpheus in the Matrix, an almost mythical, wise black guy who shows up in a pretty unexplained way, speaks in deep sayings and helps our white protagonist reach the setup of the story, enlightening him.
More recently, we can take a look at BSG, where our spiritual guide character who helps Roslin find her destiny... is a black woman preacher, neatly disposed of once her plot role is complete (to be replaced by the black Gemanese councilwoman, who shows up occasionally to answer useful spiritual questions to the advancement of Roslin). On a show heavily devoid of black characters, this sticks out like sore thumb.
Now any instance in and of itself is just a story choice, I'm not trying to say 'ZOMG DOCTOR HOO IS TEH RACIST' - I think you know me better than that

it's just when you see the same thing happen again, and again, and again, across pretty much all genres of fiction, it's hard to pretend that you
don't see it.
Not to turn this into a racial topic, but the exact opposite is the whole Magic White Kid syndrome, too. The Forbidden Kingdom and Transformers were supremely guilty of this, wherein the vastly superior but clearly minority
supporting cast relied heavily on who we would consider to be normal to save the day. When you start upstaging Jet Li, Jackie Chan, and the mighty
Autobots, something's wrong
I don't know if I can blame anyone, however, simply because both that and the Magic Negro concept is so ingrained in all our heads now that it's almost a subconscious thing to write like that. It's so subversive.
Anyway, I digress...
Back to the episode, I wouldn't define it as campy (okay, flying bus), but simply... meh. Just meh. I have a hard time believing that billions of creatures would move so fast that they would naturally create wormholes, but it takes them an hour to reach our heroes (does that mean if we give everyone on Earth a segue, we can travel to another planet?). However, I do like the design and the explanation given for the carnivorous creatures. Like the Weeping Angels and the Reapers, nuWho seems to do a consistently creative job of showing imaginative evolution.
Christina was a bit of fun, but yes, she was cliche (did she HAVE to be an aristocrat?). I do like how the episode pointed out how similar she and the Doctor were and that she was essentially a match for him. Someone earlier made the excellent point that she really was no different than Jenny; normally that wouldn't bother me, but with that point in hindsight, I'm now a bit disappointed that we saw her thieve in the prologue, to explain why she was so super-capable. If the episode started with her running from the police and just happens to catch the very same bus our Doctor was on, the mystery of why anyone would have an ax and a spade in her backpack would help the character so much.
Speaking of which: That was arguably the worst bunch of fictionalized security guards I have ever seen. Sure, security guards are almost always cannon fodder in film and TV, but this was just downright embarrassing even for cannon fodder standards.
UNIT was alright, but Magambo threatening Malcolm at gunpoint was a bit extreme. Yes, I realize that she is military and her orders are to be followed, but she seemed more bitter about being left out of the loop rather than being concerned about the safety of the world. One wouldn't get that impression had the gun not been drawn. Thus, it seemed like phony, shoehorned drama. "We have 15 minutes to kill! How can we add false tension?"
My problem with RTD scripts is how wildly inconsistent the scale is. A 20 foot hole growing to 4 miles and then 10 miles? This goes along with the planet-tractor, 5 million Cybermen across the world, people conveniently dismissing large scale invasions, and other outlandish concepts, in that the scale just doesn't seem to match what's going on screen. We could believe the Daleks were bombing continents because it happened where the action/plot
wasn't happening. Heck, for that matter, did the bus really need to fly that high? Even with the simple things, there's less and less moderation anymore, with the defense being "Doctor Who has always been outlandish!" I would argue that it's been outlandish for good reason.
As for Lee Evans, he was good for the wow factor when he first came on (I avoided all spoilers as much as possible). Seeing him in a science role and very eccentrically so made me wonder how he would do as a Doctor himself (who else would name a unit of measurement after himself? Wonderful!), though the whole "I love you" part was a bit unbelievable, even for him.
In the past, I never really connected with the idea that Murray Gold's music was too much, in terms of use and composition. I thought he had always done fine work. In this episode however, the music did seem to blare almost inappropriately to the point of distraction. I'd get interested in dialogue, only to find that the music itself was getting in my way of understanding/enjoying the script. Time to tone it down.
All in all, not a bad episode, but not a good one either. I'd have to give this a borderline average rating.