1) What I had missing on the Group page is that, it doesn't have a summary of who owe who and what amount. You mention a total amount owed by a person in the group but to whom. ANd if one wants to see to whom he owes, he need to calculate the total amount from different bills paid by one person.
I would prefer to have a kind of summary that lets say:
you owe X€ to John.
you owe Y€ to Michelle.

2) On the dashboard, the bill are not well shuffled with each one after some items are added within a group. Lets say out of group John owes me X€ and as a part of group John owes me Y€. I should have a value saying "John owes you (X+Y)€". Similarly, there is possibility that John owes me X€ out of a group but then I owe John Y€ in one group. So on the dashboard I should have one value which either I owe John or John owes me instead of two statements:
John owes u X€.

You owe to group Y€.

I hope I explained you the well enough.