I never really took Saren for some wildly competent tactician that sees through all of our best laid plans, since he's just a simple pawn of the reapers, just like the geth are. As for the bomb, the way I see it, anyone and everyone tending to it is going to take one for the team, and the best course of action is to leave it to anyone still standing there to hold off the geth long enough for everyone else to escape. Plus, I greatly prefer the way the scene looks when the person at the bomb still has a little fight left in them, just to see the Normandy make its escape before the explosion, and since Kaiden is the one I consider to be more qualified to deal with the nuke, well, his fate is pretty much sealed in all subsequent playthroughs. Part of it does have to do with what I think is the most logical course of action, but a big thing also is just how it really looks in the story too. For me, leaving the bomb tech behind just looks way more dramatic.
As for being a Spectre, the reason I consider this to be irrelevant to either character's qualifications is because it's all a lie, a ploy conjured up by Udina.
Yeah, but I hate stupid villains, pawn or no pawn so I like the idea of him being smart enough not to follow around a distraction team. I save that thinking for the Heretic Geth. And I wouldn't want to run the risk of letting one person defend a bomb. The Geth could easily kill that person, disable the bomb with whatever superior tech skills they have and call it a day.
I do like the idea of making a choice based on drama though. That's why I leave Wrex alive, save the data, then sabotage the cure. It shows how desperate Shepard is in ME3 to stop the Reapers to the point of betraying his friends. And the showdown with Wrex is just awesome.
As for Udina, I agree. But a lie should at least contain some elements of truth to be believable. I can see how Kaidan would be qualified enough for the role. Can't see the same with Ash.
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I don't like Geralt with a long beard but I do think he looks nice with his beard trimmed short. But I think he look at his best when his beard is just coming in. When the stubble is a bit thick. I keep shaving it just to see it reach that point.