On Dec 8 the Japanese figured they had caught the Allies completely flat footed. Sending the B-17s to the bases in Formosa probably would have caught the Japanese bombers just getting off the ground and may not have encountered any CAP at all. In any case, the B-17s operated higher than the Japanese fighters could handle. Such a raid might have saved Cavite and the Philippine fighter force for a few weeks.
Bill
Interesting speculation but would muck this game for the Japanese Player so bad he would never recover. Be an interesting possibility only in a game that was limited to the PI/DEI/Malaya and ended after 100 turns or so like the Rising Sun Scenario in vanilla WitP. A tactical disaster/problem early on might by skillful Jappanese play be overcome in the short term.