Here is my take on the Cut-off ranges:-
(1) Dismiss all bogus claims and estimations that the cut-off would be in range of 230-240. Don't even hyperventilate on scores around 200-220. Cut off is going to be far lesser than that.
(2) There are many of us who have done well on Paper II (ranging from exceptional to above avg.) but have failed somewhat to strike a chord with Paper I. And this is the genesis of all the sectional cut-off talks. There are people who have scored as high as 170-180 in Paper II but there marks in Paper I linger around 45-50. As per my opinion there is less hope for such candidates as the test here is not to check ur ability to quick solving and reading passages. It is more than that and GS is an instrumental key that unlocks the portal for the mains. So what should be a logical explanation here?
(3) Hypothetically if a person scores 200/200 in Paper II (Don't sweat. There would be no one in that category) and scores 50 in Paper I, his ratio of paper I to paper II would be 1:4. To me thats quite an irrational ratio and defeats the entire idea of bringing forth analytical and rational minds for the top job. As per my estimation this ratio would be 1:3 (max. possible). For instance:- If cut off is 200 (hypothetical) and a person scores 50 in GS and 150 in CSAT he is through. On the other hand a candidate who scores 30 in GS and 180 in CSAT should be held back as his ratio is 1:6. (However I can't commit that this would be the strategy employed by UPSC. To me it sounds rational and logical).
(4) Coming to sectional cut-offs, let us assume that the topper of prelims gets a score of 130 in paper I (65 ques. correct), then the individual cutoffs shoule be around 1/4th to 1/3rd of the topper's marks. So there is no possible need to fret on the issue. Sectional cutoffs are quite low and are only the minimum benchmark criteria. I have heard of people qualifying with 36/150 in GS last year in General category i.e. 24% of the total marks.
(5) On a rough estimation sectional cut-off should be around 40-45 for GS and 70-80 for CSAT. Anyone with marks above that should stop worrying about the sectional stuff.
(6) Coming to cumulative cutoffs, last year it was as low as 33%. Considering paper was easier this time (CSAT) and more time was on hand (GS) but keeping in mind extremely analytical questions in GS the cut-off should hover around 33-37% i.e. 132-150. Anyone with a score above 150 has a very good chance to make it and shall concentrate fully on the mains preps. Also cut-offs for SC, ST and OBC shouldn't be really down as in 10-15 marks below the General category. It would be 2-5 marks lesser than the General Category. (Also the people with reservation category who are worrying if there is reservation is prelims and have seen the Delhi HC judgment in this regard shall be relieved that a stay has been obtained on the same).
Concluding my estimation for cut-off is 132-150. And all people who have a genuine expectation of attaining the same shall stop any more meanderings, quit with checking answer keys and brooding over the missed and silly mistakes. It is time to rise and shine and get on a rollercoaster mode for the mains. Wish you all happy studying.