Davis suppose to be a blocking TE, Boeman I think has some good speed and decent blocker who can get downfield. ASJ definitely needs to save this group of misfits.
I think it's because Amaro didn't really care. Based on comments I read, he seemed rather blase and unconcerned whether he would make the team. He's soft and didn't bust his butt to get better. I think Bowles wanted players, who while they might have been more limited players, worked hard and gave their best. Building a winning football team isn't just about having the best 53 players in the NFL on your team. It's also about attitude, work ethic, chemistry, etc.
Which is why they brought in nose to the grindstone & shoulder to the wheel, hard working, terrific character and work ethic, blue collar having Austin Seferian Jenkins. Of course, it all makes sense now. He cares, unlike Amaro.
