Garmin notification handling is very basic- you can see a notification and you can dismiss it.
Notification Center For Pebble does much more. It uses a companion Android app and optionally (?) the Android Wear app and API to allow you to delete incoming email, filter notifications, respond to incoming texts with canned responses, and much more.
I want my Garmin watch to be able to do this too.
I corresponded with the apps' developer, and though he has no plans on moving over to the Garmin ecosystem, he would be glad to see someone continue his app on a non-Pebble platform.
His source code is already available, but not being a programmer myself, I don't know how difficult it would be to convert to the ConnectIQ API and Monkey C. So I'll underestimate things and say that it should be easy :)
If that's too much to bite off at once, maybe start with something smaller, like converting the Pebble Dash API to work with the Garmin Connect app and port the simple Dual Gauge watch app over as a widget. Bonus: you'd get a phone battery gauge on ConnectIQ. Wait a while and I think the developer will release Pebble Dashboard (which is the predecessor to the Dash API) as open source.
Yeah, I'd love it if Dashboard was also ported over. Just think: wifi, Bluetooth, modem, ringer, and backlight control from your Garmin watch.
Then all I'd need is a good calendar app and Garmin will be a compelling Pebble replacement and upgrade.