Hey Strike,
You are absolutely right with your comments. The best way to really find out about a ball is to speak with someone who is knowledgeable about that particular ball, or watch it roll first hand.
I also agree with your comment about the "recommended lane conditions". BUT, we have to be very general with that information because alot of balls can handle everything between med light to med heavy depending on how the bowler drills it and how they finish the surface. The biggest problem we run into when trying to describe a balls reaction is that my medium could be heavy oil for you, and it could be light oil for someone else. There are areas across the country where the standard house shot would be considered a flood for people on the east coast or in the south.
A perfect example of this would be a trip I made to Texas a couple months ago for the TCBA All Star Tournament. Most of the bowlers there thought the condition was a medium to a little heavier pattern. A lot of bowlers were having trouble getting their equipment to finish. I had some equipment with me and tossed a couple games, and compared to the lane conditions around here, they would have been considered really dry.
On the opposite side of this, a couple years back I made a run through California, and bowled a couple games with one of my sales reps out there, and what they thought was normal medium conditions would have been considered pretty wet here in St Louis.
We do our best to take a middle of the road approach, and describe the equipment based on what we think the vast majority of bowlers would consider light, medium, or heavy. It does not always apply to everyone, but if you compare ball to ball it should give you a reasonable idea.
Jason