Maybe for PvP - can't really comment on that. That's about the only time people use the 20/20 fire facet monarch's I think.
But for normal PvM, I think Infinity merc and a griffons along with factes in the rest of your gear more than gets the job done. I'd prefer a Spirit for the FCR, +2 skills and FHR. If you really want more facets on your gear you could use a non-runeword shield (better for blocking anyway) and drop a few facets in.