I have to take exception to the premise that the O-line has improved over the latter part of the season. The Texans have allowed over 3.2 sacks/game in December, compared to 2.7 in the previous games. Davis rushed for 150 yards in the last game, but half of his 30 attempts went for 1 yard or less. That's not an indication of a consistent line.
What has been consistent about the Texans offense is the inability to put TDs on the board. The offense has scored more than 2 TDs in a game only twice this season. Both occasions in hurry up offenses when down by 3 scores. Lately, the book on the Texans is to tackle the RB on the way to the QB. Davis has had some big games, but teams aren't afraid of him. They are afraid of Carr & AJ. If the Texan O-line can't protect Carr, this offense will never work.
The idea that the line will automatically improve if just left alone is based on some faulty logic. One, the reason the Chiefs & Broncos line has remained together is because they are good. If they weren't getting results, those teams would fix the problems. Two, I understand the logic that Wand & Pitts could turn the corner with another year under their belt. But that just doesn't hold for McKinney (7 year vet) & Wiegert (10 year vet). They've regressed and there isn’t any sound rationale that they'll turn it around next season. Bringing them back and expecting improved results doesn't make sense.
“We’re looking for a coach that...works with great energy and enthusiasm and very positive in his approach.” - Bob McNair