Strum near the bridge (the bridge itself, not the bridge pickup) then strum near the neck pickup and hear the difference. That'll give you an idea of the different 'input' the pickup is dealing with. Bridge pickups tend to have a higher outout in order to compensate for the lower volue from the strings vibration near the bridge. They also compensate for the lack of bass.
If you put a 'bridge' pickup in the middle or neck, it will obviously compensate in the same manner as before, but the input will be louder and bassier than it would have been at the bridge. So the output and amount of bass will be larger than you would get with a pickup 'voiced' for the mid position. You can deal with that somewhat by having the pickup quite low (will help a little with the bass and quite a lot with the volume) but you might find that it doesn't balance too well with the other pickups in the guitar.
There's absolutely nothing wrong with trying it, but don't go buying a new bridge pickup to try it with because you'll lose money selling it if you don't like it.
