It seems highly possible, if not in fact highly probable that CRISPR binding with nucleotides will never have as good affinity and specificity as ZFNS.
There are simply many more bonding combinations for proteins than nucleotides.
Perhaps nucleotides and proteins could be combined, or perhaps there are more specific and higher affinity binding proteins than zinc finger nucleases, or perhaps there is some other completely different system like sleeping beauty.
But there is good technical reason to suggest that CRISPR will never bind with the specificity and affinity of ZFNs.