Personally I felt the system was heavily cut back due to the 30 fruit goal. If the levels had, say, a end of stage goal like Yoshi Island, the scoring system for the levels might've gone into the 10K area since there is the melons, coins and lucky fruit that increase your score ten-fold, along with killing enemies your color.
Yes, I experimented with this one time. A shame Yoshi's Story has flaws that keep it from being a classic it deserves to be.