Hello Aspirant! As far as BITSAT is concerned, it's always easier than JEE Main and Advanced. As far as of now, as the pattern is changed you can expect a slight change in the type of the question and the time it will take to solve the same. But difficulty level cannot be more than that of JEE that's for sure. If you study hard and practice the concepts and questions you won't find any examination difficult. It's just the pattern that has changed and not the syllabus. So solve previous year questions and mock test papers for this year. You'll definitely score well.
Hope this helps!