I use the word "gimmick" because I found the some films' depth and message revolved around these gimmicks rather than on the films' overall strength. Some of these films are good ones, of course, but some common elements nonetheless exist.
Please forgive my very infantile list... I'm simply not a film scholar like so many of you!
Many of these trends started slightly earlier, as in the late 90s.
The Motifs:
Memory Issues
1) Memento
2) OldBoy
Double Identity/Personality Disorders
1) Memento (sort of)
2) The Departed
3) OldBoy
Compulsive Disorders/Self-Medication
1) Memento
2) The Aviator
3) Garden State
Documentary/Mockumentary-style/No Tripods allowed
Too many .... too many... After getting a splitting headache from watching Rachel Getting Married, I finally had enough.
Blur of Reality and Imagination
1) Stranger than Fiction
2) Memento
3) Requiem for a Dream
Play with Sense of Time
1) Memento
2) OldBoy
3) The Case of Benjamin Button
Anti-chronological Narrative
1) Memento
2) The Case of Benjamin Button
TIA for your input.