Well, like you said, there's the concept of a "hole" and the concept of an "upgradeable position".
The goal should always be to upgrade when possible, given the limitations of the salary cap. I agree with you when you say the only real hole on offense is LG. But I think most people can see that an upgrade would be warranted at RG, RT, TE, WR, and QB. Not that I think we need, or should get, an upgrade at each of those, however.
I'm one who thinks that improved QB play will help cover up the holes and upgradeable positions more efficiently than finding new players. Better QB play will make everybody look better. I'm putting my hopes on EJ showing improvement in year 2. If that's the case, then on offense I think the main *need* is for an upgrade at LG. I think the outcomes would be significantly better with improved QB play and a better player at LG. The rest of those positions -- RG, RT, TE, WR -- probably give you less bang for the buck, given who we currently have there.
And yes, we definitely need an upgrade to the Bradham/Moats position. Get a stud LB in the middle and move Kiko outside, and now you're talking. As long as we keep Byrd.