Despite his hair-trigger temper in his personal life, professionally Alec Baldwin seems to keep that in check. There's no denying his intellect, and he does have a political science degree which qualifies him - much more than many cable news anchors - for such a position.
Maybe, as the timeslot is 10pm once a week on Fridays [memo to MSNBC: time to replay the Friday primetime lineup as you do every other night, as the West Coast deserves a reasonable chance to see them in primetime] he may opt for a more comic look at the week's events. Of course, he probably hasn't got a chance because Bill Maher is on at that exact time and I doubt any of those viewers switch (DVR maybe?).
At the very least, it's one less hour of MSNBC's interminable prison shows.