Giridhar offers some observations on JEE, mixing them together with his thoughts on GATE. [Especially on the latter, Giridhar can speak with deep knowledge, as he was the Deputy Chairman of GATE at IISc several years ago]. Here's an interesting bit:
I know that one of the measures that is being thought of is to only allow candidates who have represented the country in the (Math/Physics) Olympiad OR secured an average plus two standard deviations in their respective board exam to write JEE. Because most of the board exams follow a normal distribution, only the top 2.5% will be allowed to write JEE. JEE will not be an objective exam (i.e., multiple choice questions) but will include several descriptive questions with marks ranging from 1 to 10 for each question. Subsequent to this exam, JEE will announce the marks in each subject for every student that took the exam. The departments in each IIT will decide the weight to each subject. The candidate then decides which branch to apply and to the IIT that (s)he likes. Computer science may give 60% weight to marks in maths and 20% weight each to physics and chemistry. The maths department in IIT may give 90% weight to marks in maths and the candidate can join for M.Sc (Maths) there.