I am 100% for this. The Bills have a ton of cap space. Take a look at the Bills biggest needs, O line and WR. Take a look at the available free agent linemen and recievers - it is awful. You could get Bell for probably 19 million a year (or less). McCoy cap savings (approx 6 mil), if cut, and getting Bell would give stability to the position for at least the next 3 or so years. What else are they going to do with the cap space they so desperately worked for. If there were other free agents in positions of need I would be all for it, but the list is pathetic.
P.S. he is also very good out of the back field. A true dual threat.