@adamdbradley I think you closed #3 in a rush.

angularfire2 and firebase are something you can't ignore when thinking ionic...

It's also not specific to them, it's a problem when using rollup, I think the rollup process needs to handle commonJS directories transparently.

I now have another, similar error with lodash

When I:

import { assign } from 'lodash'; 

I get:

[14:02:04] bundle failed: Error: Module /app/node_modules/lodash/lodash.js does not export assign (imported by /app/.tmp/data-source/some.service.js) 

Again, there is a workaround but ionic developer shouldn't get hard time on simple tasks:

import assign from 'lodash/assign'; 

This is not perfect, there is a TS error:

[14:14:40] src/data-source/feeding.service.ts(5,8): error TS1192: Module '"lodash/assign"' has no default export. 

There's a switch in error between the 2, when TS is happy rollup isn't and vice versa.

BTW, rollup does a wired thing when doing:

import * as assign from 'lodash/assign'; 

assign will be the module, with a default property which is the assign function...

error_handler.js:45 EXCEPTION: Error in ./HomePage class HomePage - inline template:17:10 caused by: assign$2 is not a function 

I know you considered #3 as someone else's problem but app-scripts is part of the ionic CLI and if the integration is not smooth you'll get ton's of complaints.
If you integrate rollup you need it to be transparent.