IIRC, initially he would make some effort to mimic. The skits during the primaries he tried to at least get the odd speech pattern.
Then last week the guy just phoned it in and this week as well. I guess it was ok to mock him as the candidate but now as Prez they are too leery to do so.
I remember the same. They never made fun of his use of the teleprompter; and his jerking his head back and forth between the 'prompters' ... nor his stuttering. But originally the actor did try to mimic Obama's staccato voice pattern. I didn't see tonight's show (I'm on the left coast), but I agree that the actor/'comic' just phoned in his effort last week... and it sounds like it was more of the same this week.
I'll pass.