I've never worried about the outline my horses go in... I'd rather that they were responsive and obedient. Once they've got that then the rest tends to come in time IMO.
When I got him Ron was typically all up front, head up, and hollow, but he was also ignorant, and stubborn. I spent my time just asking him patiently to respond promptly and correctly from the leg and weight aids. Now, 8 years later, he works from a massive powerhouse behind, does basic lateral work, and responds to weight aids alone if required... he also goes in a longer, lower more rounded outline, of his own accord, and is more uphill. all without me really trying, and absolutely not fighting with him about it!!