JMSDF has its own long-range, super-sonic ASROC. It is using Japanese light-weight torpedo, which is much heavier than Mk.46/54. So, I think it can relatively easily accommodate Stingray if you like
On the other hand, I think there will be two types of range requirements for ASROC.
A- If the enemy SSK is 10nm away, a torpedo even with its top speed of 40 knots needs 15 minutes to reach us. Long enough to deploy an array of decoys. Even in ASM world, soft kill prevails. Under-water sensing is much much much much complicated and difficult, so I understand the soft-kill is very effective. (It is only when the enemy subs is located within 3-4 nm, in which case 5 minutes is not enough to deploy the decoys efficiently.) In this case, the range will be defined by "how long time is needed to deploy decoys".
B- On the other hand, if we want to react to the SSK, to force them cut the torpedo wire to escape, long range will be important. I think Japanese ASROC is aiming at it. In this case, the range will be defined by "how far our sensor can detect enemy subs".
As you know, Range of B is sometimes SHORTER than that of A, which makes is complicated.
But I do agree even a classic VL-ASROC, which is at least good at "A", will be of great importance for T26.