ndansmith wrote:"This a second-class condition so the condition is false (at least for the sake of argument). So from the author's perspective, Jesus was never on Earth because the verb is past tense."
The funny thing is that this argument would also apply to English, where you have the past (subjunctive) "were" (and even "would" is historically a past form, I believe). For Greek, I'd say that basically in these unreal contexts, the imperfect represents present time and the aorist past time, so I agree with Irene that that English translation is perfectly fine.
(Of course, this just shows that Greek had no tense at all )