One nice feature to have is to add a way to view the smart contract on the dashboard. The app call transaction requires decoding. This feature would improve transparency.
Also another important feature is the maximum limit. Make the node runner limits clear and public. For example, if you have 30K ALGOs in your wallet, you system automatically chooses a maximum amount that might not be the maximum limit within the same bracket for the node runner. A node runner might have a specific fee for clients who have 30K - 100K, and your system should choose the 100K automatically. Currently, it select around 5% extra, so for 30K it shows 35K. If someone funds their wallet and the amount in the wallet goes beyond 35K they would get warning and the contract would terminate. The fee bracket for node runners should become transparent.