First of all great article @reverseacid. You explained smart contracts and issues with smart contract very well.

There are surely many cases when it comes to smart contracts. There are many possibilities. Suppose "Mr. C" is the customer who is paying for some task and "Mr. S" is the seller or the freelancer who is doing the job. There are many possibilities and ways that people can play with smart contracts. With different kind of smart contracts, there are many loopholes using which Client or the seller can do the fraud.

I think following system can work :

The customer creates the order - the fund will be stored in the wallet - Seller submits the files - Fund will be release once customer confirm the delivery - fund will be released but there will be some freezing time and seller will get the fund after a certain time, let's take 7 days of freezing time.

Why freezing time ?

• So can customer can test files properly and make sure he got the right things. In case he found some issue he can discuss with the seller.
• they can discuss the problem and if not come on the mutual agreement then Client or seller can open "dispute" and can involve the third party means the person from the platform they are using and then it can be resolved based on the proof.
• In the dispute third party/platform person can refund the customer or release to seller without any issue.

I don't know if this is the proper solution. But suggested this based on some most popular site's concept.