I think this coin would be more decentralized, if Proof-of-Working-Stake has a limit 1000 or maximum 10000 Clams,
What do you mean by that? 1000 CLAMs per address? Wouldn't people just split their coins into multiple addresses? I don't see how you are going to be able to limit the amount of CLAMs any person can stake when you have no way of knowing which addresses are owned by which people.
because Just-Dice have almost all coins and it is centralized.
Just-Dice has less than 50% of the CLAMs that have been dug up, and way less than 50% of all the CLAMs.
There is no incentive for users to stake, if exists so big PoSW miner.
The incentive is that you earn CLAMs for staking. Just-Dice takes a 10% commission on staking in order to make using Just-Dice less attractive than solo-staking.
It shouldn't affect your incentive whether a single entity is staking 1 million CLAMs or if 1000 entities are staking 1000 CLAMs each. Your wallet will be the same percentage of the total in either case.