But isn't this just the hindsight talking? Both of you can't help looking at the image with today's perspective, and the knowledge of WC4. Try imagining seeing it as the very first thing you see for WC4, when you do not yet know anything else. The only real point being communicated in that teaser image was that there is a new Wing Commander, the Kilrathi are not involved, the bad guys are humans, and that Blair and Tolwyn are both in it, in unknown capacity. The shadowy figure, as far as you would have been concerned, is not actually Seether - it's just an ominous shadowy figure, who is only there to tell us that the bad guys are humans.
What if it had been Tolwyn in the background, and Seether in front? Well, all that your 1995 self would have gained from such an arrangement is the knowledge that there is someone new involved, and he looks mean. Presumably, Tolwyn in the background would have been as unrecognisable as Seether currently is (you can only recognise him today because you know who he is)... or, if he were recognisable, then this would be a major spoiler, because the dark shadowy position is much more ominous than standing back-to-back with Blair, with whom he's always had a rocky relationship anyway. At the time, a much more plausible interpretation of the image as it is, would have been that Blair and Tolwyn must set aside their differences to combat a dark new human menace. But put Tolwyn in the background, and that no longer works.
I also don't see how replacing Seether would have helped. Setting aside the difficulty of putting Tolwyn in the background, what would be the appeal of seeing Blair and Eisen up front? We just had a game with Blair and Eisen in the lead roles. Why would this be exciting? The message that this is just like WC3, except without the cats, seems rather anti-climactic. And if you think about it, there really isn't anyone else from the WC4 cast that you could place there. If Seether were placed in the foreground, he'd work far better than Eisen or any other character, for the exact reason that he is new.