Thanks for posting up the M15 definitions of the ELU and BCV attributes. I've read them as well.
If you read in between the lines, it seems you can interpret the way M15 describes the ELU and BCV attributes to that of M25's definitions, and also how they may still yet work.
ELU for M15: Increase Elusiveness to quickly get away from contact. Elusiveness is important right before the tackle.
The first line can possibly be interpreted as the ability to shed tackles, being able to "quickly get away from contact." As for the second line of that definition, I don't how to interpret that one. No comparisons to the M25 definition for the second sentence.
BCV for M15: Increase Ball Carrier Vision to read the running lanes. Ball Carrier Vision is important when making quick adjustments.
I believe the first sentence here just sets up the meaning of this attribute in the second sentence of the definition. The first sentence is just telling us what it would "naturally" do for a RB, while the second sentence can be interpreted when reading the, "is important when making quick adjustments" line. That can possibly be interpreted as to what some feel like is the RB weaving between the line, side-stepping an O-lineman, or slightly pushing off an O-lineman , all while keeping his balance.. which would all be quick adjustments or shifts in a RB's movements when physically interacting with his O-line.
Just a thought, as I would love to actually know for a fact on what these two attributes do exactly, as I'm sure some others would, when they decide where to spread out XP to their RBs.