It should be noted that there are a fair few Dragoon-bred trueborn, which is both good and bad. On the one hand, they'd be extreemly loyal to the Dragoons and have no place to go in the Inner Sphere. On the other, they'd be totaly unacceptable to the Clans, and likely make the remainder of the Dragoons totaly unacceptable.
Really, I think the point has been made that any decision to accept a Clan return order has to go back to either 3017 or better yet 3000. There's reason to think that the Dragoons were never intended to come back right from the get go (based on their unhesitating acceptance of the 3017 orders, amoung other things) but its quite clear that after that, the stepts taken (setting up omni mech manufacturing, a breeding program, etc) make it quite clear that they had accepted their mission and made plans to stay in the Inner Sphere.
Had their orders from day one been "you're going to come back and join the invasion and we'll really make use of your intel and your skills, seriously" and had the leaders (either the Wolf brothers or some diehard crusaders picked in their place) accepted that and trained their people that way, then sure its possible. Of course, an inability to recrute may have left the force closer to a regement (or a company, if they don't add anyone), so the resualt would have been a lot less pronounced than if the Dragoons came as they did in Canon with five Clantech regements of elite warriors and heavy supporting forces. But, a force raised by the Warden Wolves as a delaying tactic in the first place was always going to be more likely not to come home than to come home.