While I don't care how many reps he can do, a CB needs good upper body strength to fight through blocks and jam the receiver at the line. He should be able to do better than 4. I could do better than 4 as a sophmore in HS.
Bench press is the least important combine stat for a DB. His 40 time helps, but his interviews and film will have the biggest impact. The film will show poor man coverage. The interviews only the teams know. Ball hawking ability and return skills get him in the league. Hard work and keeping his nose/bong clean give him an NFL career. He has more potential than T'eo, but is a bigger gamble.
Poor man coverage in 1 game. What AJ and Bama did against Tyrann in the national championship game was play mistake free football when attacking him. Tyrann was still good in man coverage. You have to throw a perfect pass and make a perfect catch and hold on to the ball. If not you will get exploited. Ask Jacoby Brissett, and Andre Debose, or Ryan Tannehill and Ryan Swope.
99.9% of his big plays were playing nickel. He was absolutely exposed playing corner. Doesn't mean he can't play it, just means he has work to do. Not NFL CB ready, out of FB for a year and off the field problems drop his draft pisition. However if he gets his act together someone could get an impact player at a steal of a deal. Much depends on where his head is.
His natural position is nickel or free safety where is ability to read and make the big play is enhanced, but to say he was exposed at corner is going a little far. His lack of height is his main problem not his skill.
Good article breaking down his combine performance. http://m.bleacherreport.com/articles/1544917-breaking-down-tyrann-mathieus-nfl-combine-performance
So because of his bench we are now questioning the physicality of tyrann? He was sure very physical on staurdays to me. Just because some people do not perform well in NFL combines doesn't mean they cannot play the game. We put WAY to much stock in the combine.....all I care about is how a player performs when they strap it up.
TM's bench would be the least of my worries, well behind off field conduct and playmaking ability. I hope the latter two are under control, and he has a successful career.