I think I noticed somewhere else that the OP has chosen to dive a backplate/wing rather than a BC.the S90/S95 is still too big to stay in "normal" bcd pockets
Strobes are definitely nice ~ but not everyone ends up getting one. I've been doing without one for years and since I started using continuous lighting with good success I might never get a strobe.Using a external strobe will greatly enhance your photos and you will soon get one, belive me.
This was taken with continous lighting (diffused HID) in water conditions that were *dusty* enough a strobe would have turned it into a snow scene. That and the diffused HID seems to attract some fish.
If I read correctly, the OP wanted simplicity without the photography "taking over" the dive. And if the OP ends up getting an HID canister light there is the continuous lighting already at hand.
Backplate/wing/harness with a clipped off point`n`shoot. Not for everyone and not for everywhere... but maybe the simplicity that the OP is looking for.