If there is to be a change in the way we are taxed, what ____ you prefer as a replacement?
I'm puzzled why more agree with "would" than with "will". IMHO, "would' should have been more agreeable if "there were" instead of "there is" had been used.
The 'if' clause remains fairly hypothetical, so 'would' is better. One can see why the 'if' clause might use 'is' in some circumstances, but the question remains speculative