The different handle materials offered by RMK and throughout the knife world these days add much to the pleasure of collecting and using "man's oldest tool". Of course I can't say enough about stag, wood and other natural (non-leather) materials. Regarding a stacked leather handle, I agree, it is a wonderful handle material but I have personally observed how, over time and with use,scratches/cuts/gouges appear, dirt and skin oils, sunscreen, insecticide and food prep/cooking stains appear and become sealed in the leather when protection treated. This can add great character to the knife but the owner/user must accept the dynamic leather qualities. This is where micarta shines; tough, stable, beautiful, dependable, can be sculpted and is virtually impervious to all the things that affect leather. The RMK I own with a micarta handle is the #16 Diver's Knife, a good sized tough as nails utility/survival/combat-ready knife that will withstand just about anything including salt water.
Micarta is probably the only handle material that even makes sense in this application and, to my mind, the one handle material with the equivalent of a "no regrets" guarantee built in!