Marine lance corporals, corporals to face promotion review boards

Not at all. Marines through Sergeant are still promoted "statistically" (Composite/Cutting Score). This is designed as a mentoring tool to see if Marines are doing everything they need to do to maximize said scores and are ready to take on more leadership responsibilities.

I "think" it is akin to the Army's board process, but much more informal in nature. Guidance thus far is "no general knowledge."

The "Terminal Lance" phenomena is a result of Billet Allocation. Because we only "auto-promote to LCpl, and statistically promote above (Full Board at SSgt +) it creates a funnel effect. The Army likely has a similar issue at Specialist, but it's less apparent because of the TIS/TIG requirements going from E3 to E4 to E5. For Marines, it's very easy to hit E3 right out of MOS School, which means you can sit there for 3~ years.

As a counter example, because of my MOS, I picked up Cpl fast (about a year), but sat there for almost 3 until almost every other Cpl or Sgt either got out or got promoted to SSgt respectively. I had a Sniper Private (while I was a Cpl) that worked for me that pinned on Sergeant (while I was still a Cpl). Just the way the system worked. If I has stayed in however, I would have pinned on MSgt/1st Sgt before him by 2~ years easily though.

Sgt Aaron Kennedy, MS - this is why a lot of 03xx became computer techs, because it promoted alot faster and it was more useful in the outside world.

Sgt Gus Laskaris - dont get me wrong, i wasnt down talking 03xx.