B737 First Officer expressed concern about his carrier's practice of deferring maintenance discrepancies for repair at night whenever possible.

Narrative

During preflight the engine #1 thrust reverser Krueger door seal fairing was found to be broken. This is a composite material part that is routinely cracked at the bolt holes. I was concerned about this one because it was completely/nearly completely through at about the 2/3rd point. This event went on for about 4 hours from discovery to departure. About every half hour or so I went down to the engine to see what fresh information I could bring back to the Captain. At some point; the broken forward third of the part was removed and a sealant applied to the ragged edge. I informed the Captain. Maintenance Control agreed with the Captain that CDL's generally don't apply to partial part removals. Maintenance was able to obtain a variance from Boeing. The second sign off was acceptable to the Captain. This is my third ordeal with questionable maintenance this week. I am concerned that excessive management pressure to MEL everything during the day and fix at night is causing unsafe maintenance practices.