Is it important to produce uniform random permutation?

when we make randomize algorithm ,sometimes we randomize the input by permuting the given input array. Is it important to produce uniform random permutation? Because when i use the first code give better result than original code (Fisher-Yates Shuffle)

//mycode
n = A.length
for i = 1 to n
    j = Random(i,n)
    swap A[j] with A[j+1]

//Fisher-Yates Shuffle
n = A.length
for i = 1 to n
    swap A[i] with A[Random(i,n)]