dawood! i just got to read your post on another thread and came to know that you are a ninth grade student.
first of all, it is great to have youngsters posting in this forum.a hearty welcome to you. i am looking forward to sharing our mutual love for the game with you in this forum.
since you are very serious about your opinion, I realize that I should be more sincere in my replies to you.
so here is my take.
i have come to realize that it is impossible to reach a particular level of success in a competitive industry unless there is some steel in you. international sport is very very competitive.
both sehwag and hayden have scored more than 7000 runs in over 100 tests. they have scored hundreds against all test playing nations more than once. they average around the 50 run mark. all this means they both were exceptionally good. they are unlikely to miss out on the top 100 test batsmen of all time list.
to be so good, they both must have had a lot of steel in them. so it will be impossible to compare them on their courage, self belief, positive attitude etc. they must have had these in abundance otherwise they would not have done so well for so long.
it is perfectly legitimate to compare them on more tangible cricketing elements though. their style, success in all conditions, technical glitches, technical strengths, stats, and their impact on their team performance. so if you want to keep this debate on track, and you must because this is a legitimate comparison, then please don't bring in vague terms and definitions.
it ultimately boils down to the bat swing connecting with the ball at the correct time in the correct angle. your anticipation, hand-eye coordination, foot movement, forearm power, timing and placement all combine to do exactly this. because of individual physical attributes, we succeed and fail in different degrees.
for example, i hit myself in the toe every time i bat. my longest innings in the past 12 years lasted seven balls, all lobbed at knee height.
viru could stand and deliver his shots because he had great hand eye coordination and his timing was impeccable. without moving his feet he could reach the ball at the right time with the right part of his bat. this style became his weakness in bouncing and swinging conditions. still, he scored hundreds in england, australia and south africa.
the muscular, front foot pressing attacking style of hayden's got him thousands of runs. but against fast swing bowlers of the distant past like marshall or imran he would have struggled a lot. he was lucky that he didn't play ambrose and wasim at their peaks. but again, he scored a hundred against pakistan in sharjah in extremely unfriendly conditions. that innings must rank amongst the very best ever in test cricket history.
i think there is plenty to love in each. there can be a clear cut choice between them, for sure. but that will be an individual preference rather than any gospel truth.