Funny, given how much praise the Suicide Mission got, you'd think they'd have found the money somewhere for a repeat.
I mean, the y found the money to shoehorn in MP
Shoehorn in MP? I don't see it. The folks who called MP a cynical cash-grab were right. MP was a way to cash in via microtransactions. Cut MP and the profit projections for ME3 get worse, not better; if anything, MP was subsidizing SP.
As for the SM, note that it was relatively cheap, a good deal cheaper than what Dr. Rush was proposing for ME3 if I interpreted him correctly. The ME2 cutscenes only have limited variation. No doubt some sort of equivalently cheap design could be come up with for ME3 if we work at it, though. Anyway, I doubt it was obvious pre-release that a final gameplay level which is functionally identical to ME1's, or KotOR's, would be inadequate.