<< I am considering pouring or rolling on a clear epoxy coating to reduce
water penetration and the resulting ills caused by freezing. >>
That would probably work but it is likely that the sandstone has more failing
laminations deeper down.
<< Does anyone have any suggestions beyond ripping it out and starting again
with granite or ceramic? >>
If you liked the sandstone, you may not like some of the granite that is being
peddled these days. A lot of it is really ugly, spotted gauche stuff. Ceramic
is a possibility considering the huge variety of colors, patterns, sizes, etc.
Maybe you could add a weatherproof roof over the patio with better drainage
and keep the sandstone a few more years. Good luck.