While it may not be necessary for a pastor to be trained in biblical languages, it is strongly recommended. There is no virtue in willful ignorance. A pastor or teaching elder should be as equipped as possible. No reputable seminary should grant a bible or theology degree without at least some biblical language training. Of course, there are notable exceptions. Missionaries who train indigenous men to minister in local tribes and villages may not have the opportunity to offer training in Greek and/or Hebrew. In those situations, you have to roll with what you got. But here in the States, Canada, and even most of Europe? Biblical language training is offered as part of D-Min/THM programs and even undergraduate bible degrees. In fact, in most cases, Greek and Hebrew are required courses.
Over the decades I have come to realize that the pastor is not necessarily the most knowledgeable person in the local church on biblical matters. Individual Christians have a responsibility to study the Word for themselves. I know many men who can run circles around their pastor and elders on matters of theology. But at the same time, these men lack the ministerial graces necessary for being a pastor or elder. In my opinion, each and every Christian should be as knowledgable as possible when it comes to the Word of God.