Canon G11 replacement - advice request

[Babu]

My wife has been using a Canon G11 as a point and shoot on her travels when using her DSLRs was inappropriate or too cumbersome. She has also had considerable success using it with an underwater housing whilst diving/ snorkeling. However, on our recent trip to Heron Island, the G11 played up for a while. Fortunately it came good after a reset and allowed her to use underwater mode on her dives.

She is seeking advice on what to replace it with. So far she has been reading up on the Canon G1X II (with housing) and the GoPro Hero 4 Black (waterproof) and would appreciate members' thoughts on these.
Are there any better alternatives?

[swifty]

Certainly the Canon G series has been a great P&S option for many years, especially with the availability of a relatively low cost underwater housing.
I, myself bought one specially for my honeymoon and had written about it in the product review section on Ausphotigraphy.
I can't say I've followed exactly what accessories are available for the G1x series and how much they cost but since the G1x is the big brother of the G-series, I can't imagine Canon changing that winning formula.
Purely photographically speaking there're a lot of competition in the advance P&S segment and you're really spoilt for choices. Anything from the Sony Rx series, Panasonic LX series to Canon's G7 x, G1xII's little brother.
But you'll need to look into the underwater housing options for each.
Another option you can consider is the Nikon AW1. It's already waterproof to ~15m so there's no need for additional housing if you're not limited by that depth. But it's not a fixed lens camera but will accept any of the Nikon 1 lenses although only 1 or 2 of the lenses are correspondingly waterproof too.