I’m not familiar with the Olympus.
If it was my decision to select one camera over another, I would have asked just like the OP did here. In addition, I would consider input from people like us here on ScubaBoard, which likely have hands on experience with products like these.
While I think the megapixel and raw recording capabilities do help identify which camera has more potential over another, other very important and relevant aspects to consider are:
1. How does the camera really perform when it comes to getting the shot?
2. Will the camera focus in low light or does it hunt till the cows come home?
3. Will adjusting focus mode and simple settings help users tell the camera which subject to focus on or which one you want the camera to select or is it a gamble?
4. How easy is it to check results on the spot?
5. How easy is the camera to control?
6. Does it roll video? Macro? Wide angle?
7. How are the menus? Intuitive or do they require intense training to understand?
8. Can resolution,WBalance, aperture, shutter speed, aspect ratios be easily adjusted while diving?
9. How’s the battery life?
10. How challenging could it be to service while traveling in the event something happens?
11. What are the pros suggesting, commenting or reviewing?
12. Are memory cards standard or are they special?
13. Will this require traveling with a computer, hard drives, and IT support group or just memory cards?
14. Does it have WiFi features.
15 What are consumers saying about manufacturers honoring their products?
Not saying that megapixels and raw capabilities are not important... We know they are. But if a large sensor high megapixel camera is impractical, difficult to control, impossible to acquire focus and unreliable, I’ll take a low megapixel, small sensor, slow recording speed camera that I can control, that I can tell what I expect it to focus on and will be likely very happy with a low resolution properly framed and focused image, over a higher +megapixel image that is blurry, out of focus and that required conversion from raw to jpeg.
Ricardo