The reason you add these relievers on mid-level contracts is that they are often worth it. Hunter was decent last year. So was Neshek in the half season he played. And Neshek's first contract was completely worth it, providing an All Star season.
The expense is only money, not talent from the organization.
At some point teams need to look in the mirror perhaps at their own usage patterns of relievers. Playing to win each of 162 games has led to fewer innings from starters and more from relievers and we've hit the limit of relievers on a roster. All these injuries are their own fault.
If we were salary limited we would not have signed the extra relievers. In the future we'll probably do a bit less of that because we will not need to do as much (ideally anyway). Hopefully we'll get some of the injured arms back, because I am not sure we want to see guys like JD Hammer and Yacksel Rios in important situations down the stretch. If that happens, I am guessing we'll see Klentak trade for a reliever or two that will cost more than money to address the problem.