Look guys gamers have been sticking it to the Viet Cong, the Nazis,  Middle eastern extremists, police officers and hookers for years.  These creatures are infected, they're not African villagers anymore, and the only reason some of them are dressing the way they do is because the infection is causing some of the more rural villagers to revert to older, aggressive tribal behaviour.  (One of the diaries indicates this).

I'm a firm believer that entertainment does not dictate morality or that it should even always reflect it, otherwise we'd stop punishing digital Germans for WWII.  Capcom had no intention of offending anyone with the setting and populous of the game.  In fact they raise the issue numerous times about how tragic it is that these pharmaceutical corporations are interfering in Africa in the first place.  ('Cause that never happens in real life right?)  If anything they're making a powerful statement through a horror game about how Africa has been used as the world's lab rat.  

Even the characters wearing tribal dress don't strike me as caricatures or parodies, they're people descended from warrior tribes who have been infected with a violent organism that's connected itself to their central nervous systems causing them to revert to their ancestoral dress and armament. 

The same kinds of arguments were made about  Resident Evil 4 about Spaniards, and they were just as silly.  The first few games were set in the U.S. and nobody percieved them as being anti-American.  Get over it, it's a game.  It's entertainment, and not offensive to anybody who isn't hypersensitive to such things.  Racism still exists, but let's not go looking for it in places where it wasn't intended.

Having played RE 4 about 50 times, and having bought it on all three consoles it was released for, I can say that if you liked that game you will like this one.  They've taken a few steps backwards in terms of the inventory, and the partner A.I. is helpful at times, and crushingly frustrating at others. 

Sheva will sometimes hand you ammunition from her inventory.  Sometimes this can be very useful, like when you're about to run out of shotgun ammo at a bad time to be out of shotgun ammo.  However, let's say you spy a badly needed health herb or medical spray, and  you've both got all nine of your inventory blocks filled, and one your slots contains something you can live without, like two stray rounds of pistol ammo, or a flash grenade.  You drop the unneeded item to grab the herb, and before you can pick it up Sheva shoves a bunch of pistol ammo or something into your empty pocket, preventing you from grabbing the much needed medicinal item and you end up getting killed.  So your best bet to avoid unneeded demise is to find a buddy to play online with.  I prefer to tough things out on my own the first time through, and give Co-op a go on round two, but so far this game is excellent, if not a small step backward from RE4