First class to get "thicker" mattress, too
Although the OPs title talks about J class, if you read that article he/she posted they're saying not only does J gets a mattress topper (as discussed), and First Class gets a new thicker mattress.
I already thought CX F bedding was superb. Hopefully this doesn't muck it up. They've got a good track record with bedding IMO, particularly superb bedding in F compared to pretty much every other carrier I'm familiar with in F. Despite other complaints on CX I am unabashedly loyal to CX F bedding, and I always thought marginal complaints about CX's topper (vs something like JL's gimmicky mattress "choice", IMO, which doesn't even run the full length of the bed and is far less comfy than CX IMO) were misplaced. I'm still optimistic, just worried by the maxim "if it ain't broke..."
Exact quote from SCMP is: "While in first class, ticket holders will get a thicker mattress pad, an upgrade on an existing topper used."