BB-8 is a dynamo! This droid is all the buzz right now... Even the Minions look up to this "sphere fly for the 1 eye"! Sure R2 has a great resume of saves, & adventures, but in the mobile department he lacks in speed. Although R2-D2 could fly, if you remember, with his little internal jets... But I figure the jets are a fuel base, so they would be of short term use. BB-8 on the other hand can sprint for long distances. BB-8 is clearly a huge marketing tool. I hear it's favorite line with the ladies is, "If you shake me, turn me upside down, & look at my bottom I can tell you your future!" But, no matter the action on the screen, when he darts through you can't help watch what BB-8 is doing.
I have been in research & development in the past. I wonder what was the biggest problems for each crew running the droids for the movies? I'd gather that the new design of BB-8 is a result based on the problems they had with R2 moving around. Even though BB-8 dances around, seemingly unhindered, I bet the sand still was his biggest problem. You can walk upright all day at the beach, and somehow by the end of the day you still have sand in your crack! His head floats on a magnetic field, but I bet the gap isn't all that large, so sand would stick to the sides, & find it's way into the droid. Needless to say, I'd watch a show based on the troubles of the "behind the scenes" of the set crews. It would be interesting to see the problems they face at building sets, & making the droids/ships/creatures come to life.
BB-8 is definitely an upgrade! He has potential, & character that can extend past that of R2-D2, & still communicate "through actions" to the audience as C-3PO. But will this be his downfall? Too much character allows the fans to become too attached... If we become attached, that makes BB-8 a target for termination by the bad guys. Could you see Kylo Ren using the force to implode the droid like a crushed beer can? This would paralyze it's movement making the droid worthless to help in a scene where the heroes are about to all die... Then BB-8, in a motionless heaping mound of metal, finds some heroic way to sacrifice itself to distract Kylo Ren long enough for the heroes to escape. Thus propelling BB-8 into the hall of heroes!
The Star Wars/Disney powers that be are trying to break barriers of the past. It's obvious that Rey is showing feelings for the droid, as though she would for a person. She saves BB-8 from being taken, put into robot slavery, or being junked. Maybe they will have their first droid breaking the barrier of just being in the shadows of the main characters, doing just enough to get by. Maybe they will make BB-8 the first droid to sacrifice itself to save the others? The droids in the past have been able to move about freely to do what they needed to do. Blaster fire moving all around them as though nobody gave a damn what they were doing. How often do they say, "Shoot the droids! They are going to turn off our shields/lock down the doors on us/impede our shots at the heroes!" It's as if they were wearing Harry Potter's cloak, or Gollum's "Precious" ring from LOTR. Will BB-8 finally do something to catch the eye of Kylo Ren? Will Kylo be "forced" to take action against the droid? Will BB-8 break the shadows of just being a droid, sacrifice itself, & become a true hero? Would you feel for the droid? I think I would... BB-8 may not get an Oscar, but maybe they may give the droid a metal at the end of these battles.