I've had this project in the back of my mind for a while now.
There's a very popular notion that crypto wallets like MetaMask should provide a total 'view' into a user's current accounts. They should show token balances, display NFTs, some even going as far as providing in-app token swaps.
I feel this dilutes the actual purpose of a signer. A signer exists to sign messages with your cryptographic keys. That's it.
It shouldn't care about token balances.
It shouldn't care about prices, gain and loss, or accounting.
It shouldn't care about gas.
It shouldn't care about displaying your NFTs.
It should let you create public/private keypairs securely.
It should keep your secrets secure.
It should support hardware signers.
It should show you exactly what you're signing.
It should allow you to label and manage contracts you trust, and warn you when they've changed.
It's not your window into crypto. There are a thousand dapps that do this already.
It should be Just A Signer.
As a chance to learn something about GUI programs in .Net and F#. Might as well make a signer.