User blog comment:Thewaterdragonslayer/Personal Reflections on the Differences Between 1st Generation Dragon Slayers and the Other Generations/@comment-188.171.27.28-20130207225715/@comment-219.87.176.11-20130208021716

I don't think second gen's dragon force is 'weaker' per se, but rather because second gen was probably never trained to use DS properly, if they tried to use DS magic without Dragon Force, it would not be powerful enough (I assume they CAN use DS magic without going to dragon force, as Laxus have demonstrated). So basically they NEED to go into dragon force to use Dragon Slayer magic to be of any use.

Implant the lacrima's into a first gen and you have a third gen that has best of both worlds, strong passive Dragon slayer abilities and Dragon Force at will that significantly boosts their damage.