Don't try to make sense of the future sentinels in DoFP. Singer did not do a good job. He just wanted overpowered threats to drive home the idea that this was a really bad dystopian future. It's not based on any X-Men comic I've read.
This is basically giving the sentinels the power of the dude from Heroes. Makes no sense.
The drug Xavier took to make him walk but limited his telepathy never made sense either. I don't know in what world that trade off makes sense when it comes to any sort of fictional science. Just think of Beast as a blue wizard in Singer's continuity. Like repairing a spinal injury has nothing to do with a x-gene and mutant powers.
You're suppose to just accept that this drug allows him to walk and stops his mutant ability cuz Xavier will need to walk and not be crippled the entire movie.
Beast transforming makes more sense though. Singer wanted him to be like the Hulk/a blue werewolf.