Having abusers can already be solved just with that manual withdrawal checking (since they are not stake that has huge traffic)
I wouldn't create this thread if this is the only one solution!
Verification like those are already way too far for the others gamblers. Even I can have KYC and still have multiple accounts.
Almost gambling have mandatory KYC and everyone should know they could be asked in the future. It doesn't solve 100% against abusers, but it do reduce some percentage since they need to spent more times and effort to create fake KYC.
Tightening wager requirements? Are you dumb? You just said that they should be resolving withdrawal issues but then you suggest that they should do things to prevent users to withdraw.
You're allowing an user to deposit and then directly withdraw their funds on casino? A casino isn't a mixer and they're combat against AML, the withdrawal issues happen because the manual checking, tightening wager requirements will proving they're high likely a real gambler.
If you're not a regular gambler and not familiar with gambling, you're better off to learn first before talking non sense.