The problem is; do you have the skill set to investigate these sometimes complex cases? Escrow is a difficult job, since a lot of the time you can't really decipher who's lying, and who's telling the truth. So, you need to come up with definite rules that you stick too, and remain unbiased through the process.

However, there's also a bigger problem here. It sounds like you'll be doing this manually, without any sort of previous experience. What makes you a good escrow? Why would someone use you, instead of using software that has been designed to eliminate risk for all parties.

If you could come up with a way of doing a trustless escrow, therefore you never gaining access of the funds, then you'd be onto a winner. However, that's definitely not something that's easy to achieve. Also, do remember a lot of places require a escrow license if you wish to act as a escrow.