I think that's a good idea to have family check them out if you're not familiar with either resort. There are lots that love BLT too and I would count myself as one although I haven't stayed in a GV there (yet!). And it's almost always theme park view for us at BLT- there's no better IMO at WDW. Top it off with being able to walk to MK and it's a winner. My stay a couple of years ago at VGF the monorail went down as I was waiting to board. Exactly 1 hour later I was finally walking thru bag check.

If I had been at BLT I would have been to the park in 10 minutes or less. I do like VGF and own a few points there however we book BLT more - VGF is very point intensive and I'm just as happy at BLT which has lower point requirements. I've found that if I give family members who are joining us a choice it's also what they pick.
About the points - one thing to consider is that the GV's at VGF will be more than the BLT GV's. I've toured them and they are spectacular but I tend to think all GV's are. For the week of Thanksgiving next year the requirements would be 749 points for a BLT LV GV, 903 points for the BLT MK GV and 999 points for the VGF GV. All of those are lakeview and do face the MK. And all of those are more than the AKV GV's which for the same time would be 606 points for the standard view and 657 points for the savannah view. The upfront purchase of points will likely be somewhere around 20% more for VGF vs BLT and the dues are a little more at VGF. For 2015 it was $5.05 per point for BLT and $5.52 per point for VGF.
If you sell your AKV points you will be paying somewhere around a 8-10% commission. Just trying to point out a few considerations for what you are thinking about. Maybe you even want to see about renting a GV at either BLT or VGF to see if it really will better suit your family needs since this will likely be fairly expensive exchange to sell and rebuy. You can rent out your AKV points to cover some or all of the rental costs.