Well, according to the rotational eGO server we once had back in the day, once Dustbowl would finish up and Granary would come on, it would either dip to about a half full server in the afternoons until 2Fort came on or would empty out completely in the mornings. Just never got popular in eGO (then again, no complete linear CP map has). I personally liked Granary. I liked Well more, but Granary was a good map.
As for Gravel Pit, many would say it's a good map. I don't care for it much, only because I started to hate the map once I get on defense and the team says "Don't defend A, everyone head to B." I refuse to give the map a chance, even if it has changed. For others, of course it's a good map, and it's set up perfectly. I guess the issue was at the time, it was the most difficult map admin wise, and I guess we decided to try other maps out as well.. Count completely answer this one.
P.S. Warpath is not a complete linear CP map. (That should save a few responses)