Absolutely. I don't think OB has it in him to bring the guy back, but along the terms you spelled out, absolutely he should at least be trying.I don't think it would be the end of the world if the Texans kicked the Clowney tires. He's not going to get the money he thinks he deserves until he has a banner and healthy season.
Clowney's very best season as a Texan happened when he replaced Watt at Watt's DE position. This is truly Clowney's best position.
I would offer Clowney a solid but fair 2 year contract that is guaranteed for a season. The contract would be loaded with performance bonuses. He would know from his first day back that he would be the DE opposite Watt whether the Texans are in a 3-Man or 4-Man front.
I wouldn't be crying in my beer over this optional 3 and 4 man fronts.