"Meaningfully" improved is somewhat subjective. Not sure exactly what your threshold is for meaningfully.
On the OL, it's Bradbury out, AVT in. Obviously a huge upgrade in caliber of player with health. But also a massive health risk that would leave us with Ben Brown starting, who couldn't beat out Bradbury this year. It also feels like Wilson should be better this year at C than he was at LG, but that's somewhat speculative. The depth, as of right now, is worse with Lowe gone and Munford unsigned.
FB is obviously better, but it's a lesser position. None of us can honestly say improving at FB is on an even playing level with other positions. So it goes back to the subjectivity of "meaningful".