The concept is great, and could be a game changer. It's actually very similar to a decentralized exchange prototype I built many years ago on a different blockchain that offered native tokens. I kept hoping to be able to do something similar for hive one day when it has native token support - which VSC solved with its own chain. Good job!

The infrastructure requirements will be massive. There need to be a number of validators for each supported blockchain, each keeping a full node of those chains and with a solid multisig setup that allows changes in the composition without incurring fees for moving to different addresses too often.

The collateralization of tokens with HIVE is something I didn't expect. I assume it's for security, if something goes wrong with another coin's validators/multisig? That means all this risk will be offloaded to those providing the HIVE collateral. Will they be rewarded with a dedicated token? Are there other use cases for that token to give it value?
What's the mechanism to keep the collateral ratio at 1.5 despite price changes of the assets involved?

Exciting!