It's not that you can't get good FA . . . it's that (1) you won't have the opportunity to compare offers and (2) you won't have the ability to negotiate (e.g. "School X offered me more . . . can you match that?"). So, you end up having to make the decision whether to accept or reject an offer based only on your best guess that you'll do better if you wait. If it's the kid's dream school, that's a tough call . . .
Because different schools can take the same financial data and come up with entirely different assessments of your family's ability to pay, the process is not as straightforward as one would hope.
Make good use of the schools' net price calculators, and if you decide to go with an ED application, make sure you've set very clear guidelines as to what kind of FA offer is acceptable (and what would not be acceptable) . . . and make sure your student understands those guidelines.