For the past 6 years we have taken our daughter, now 11 out of school for at least 4 to 5 days to go to WDW and in quite a few of those years we went twice within the school year. I have never had any teacher or school principal say that we shouldn't go, in fact most of them were thrilled that we had the opportunity to go. I make no excuses, this is what our family chooses to do and as long as my daughter continues to excel in school we will take our trips.
We have been fortunate that during two of those trips we were able to what the space shuttle take off, so our trips have been in my opinion learning experiences. What we also do while at WDW is make a point of talking to other guests while waiting in lines, on the buses, etc. It is amazing what we have learned about others and where they live.
Do it, take your trip and don't regret it.