Building through the draft is a smart way to go about things. It helps with cap issues because you are not handing out those big contracts to free agents. Also when you do hand out big contracts, you are usually doing it to retain the players you drafted after their first contract expires.
In a perfect world, free agency would be to add depth to the team, not to replace half the team's starters. The problem with what the Dolphins are doing is that they seem to be chasing players in free agency to be starters, but after failing to add them are using the draft as a safety net. If I were Ireland and I wanted to save my job, I would pretty much ignore free agency and the backlash it brings. Go completely into "Build through the draft mode" and "retain our players mode" and only use free agency as depth and hole filling. That is sort of being done with the addtions of Marshall, Hicks, and Westerman. Though the problem is that doesn't appear to be the inital plan that Ireland set out on.
It appeared the team wanted to add their starting quarterback to take the job from Moore in free agency. Obviously Manning had no interest, and we may never know the true reason Flynn didn't come. Was it money? Was it really that he didn't like Ireland? Or was it that Philbin didn't see him as a franchise quarterback? He also made a hail mary throw for Alex Smith, but we all knew he was never really going to leave San Francisco. So by default we got Garrard. Maybe he will surprise everyone, including myself and become a great addition. I am not so sure of that. However, while there doesn't seem to be a huge quarterback upgrade this year, it does appear Ireland is forced to make a move in the draft.
If Tannehill falls to #8 and Miami drafts him, it is very possible our quarterback position for the future could finally be settled for the first time since Marino.