This isn't a brilliant plan, but just a small change.

I like the idea of the goals function, what I would maybe suggest that besides only offering investment opportunities, we could select accounts we currently have that are geared towards that goal.

For example, I have three savings accounts I am building up to hit various goals, but I can't choose them or combine them for a single goal, so your budget app keeps saying I need invest and save more, it's not recognising that I am using those to build up to that task as I am using extra income that isn't always planned which is why I don't want set debit orders. 

Just a suggestion