The flight benefits have to come from Delta. They were asked before and came back with a solid NO. The only reason Comair has 5 years is because they were able to get it in thier contract somehow. As for unemployment, you should be able to collect while furloughed either way (vol/invol). Seniority does continue to build while furloughed, but I fully agree longevity should as well (I'd love to get the year back I lost while furloughed too). Long call reserve would be nice but you'd have to really do a good job with the rules to make it useful. The end of ready reserve would be nice too.
The problem with all these are that they are all helping the junior guys with basically nothing for the senior guys. Unfortunately as such, I am not holding my breath any of these will happen, at least not until the overall contract opens up.