This is very interesting in that IIRC we actually cut Harris and he did not make it to the 53 man roster, yet he is here, now, and contributing. So, in a way, I guess it didn't hurt to cut him.
On the other hand we obviously valued Arkin a lot more than Harris, because we made room for him on the 53 man roster and have never exposed him to the possibility of losing him to another team yet he hasn't really played for us. His upside must be deemed to be tremendous! Didn't we give a 4th round pick for him? Why would you give a 4th round pick for a guy to have him sit for several years to play? Couldn't we do that with a UDFA or a later pick? Then to keep him on the roster ...... I just don't see us doing that for a guy who just might "contribute" at some point. You only do that for a guy who you think can turn into a really good player (starter) for you. And if that is the case .... why haven't we seem him play .... at least a little bit?