I think lowering the max bet temporarily was a good move.

If this works, it undermines the conspiracy theories.  (That is, if JD profit starts rising again.)  It shows that the whale had no magical powers, and there was no mole at the data center.

Going forward:

The sliding house edge is a bad idea... it violates people's sense of fairness.

There are some very interesting ideas on letting the investors choose how much variance they're willing to accept.  These need some thinking through, but this may be the best of both worlds... it would be a way to bring the max bet back up.

I'd like to suggest a design principle: it's OK to make things more complicated for the investors, but keep things simple for the gamblers.