Most "enthusiast press" sites are already little more than advertising/hype machines to begin with. I mean really, if gametrailers.com is doing their job properly then the advertisements and actual content are indistinguishable. They're all competing for ad dollars, the same ad dollars, so what's really interesting about this is how GameInformer and IGN will be affected, now that they're not competing for ad dollars.
In terms of whether or not this will affect the actual editorial content ("teh biases," etc.) I would say probably little more than it has in the past, which might be anywhere from considerable to negligible. In other words, I don't see it changing the status quo at IGN.
For what it's worth, I don't think any of the enthusiast press sites are conspiring with advertisers to skew reviews/make more money or whatever. I do think their opinions on games are very often misleading, uninformed, poorly articulated, unpersuasive, and are applicable only to other members of the enthusiast press, but I wouldn't blame them for the lacking quality of their editorial content, or even suggest that they themselves are unaware of this situation; 28 million unique hits a month demand it be that way, exasperatingly so.
If the masses truly demanded more from them, I'm sure they would endeavor to deliver more. As it is, this merger does indeed make perfect sense.
