Roswell,
I think (only 80% sure) an SLI would require member ratification at some point. That pilot could vote.
As for a FO looking for a quick upgrade, how is that going to work at an airline with a 36 jet fleet that is not going to grow under Delta's scope? The best way for this FO to see growth is to hope for a merger which would free Delta to exercise its 36 E175, or E190 options AT MAINLINE.
It is unlikely that many (if any) mainline pilots would bid to Compass unless to improve quality of life, bases or commuting. This push is really about job security, Delta mainline growth, and closing a scope loophole.
... and lets not get confused and think a single list is right around the corner. If (a big IF) the MEC decided a single list policy benefited its pilots, it would be either a management decision to merge the lists, or a item the union had to negotiate.
Many think (me included) that management has economic reasons to consolidate Compass and mainline. But if that is not the case, it might drag all the way out to Section 6 four or five years from now.
I think it is most likely Compass will be split from the MEC, which is the first step in packaging the entity up for a cancellation of the bridges that bind Delta and Compass together. The flow & job protections will be traded away for some trinket that supposedly benefits the entire pilot group.
This "combine compass" effort is hoped to educate pilots so they see that the greatest value to our pilot group is Compass itself, or in a word, "unity." If we decide that we may want to pursue a single list in the future, that answers the question whether we want to split Compass away now.
We have another door of opportunity that is closing. If (a big IF) the pilots at Delta (and Compass since they are represented by Delta) decide that one list is worth pursuing then it holds the door open for unity.