Whenever one owns a dragon we know he can train his skills, get dragon training levels, distribute dragon attributes and equip it with dragon items. Now in addition to that I propose feeding dragons dragon shards to increase the respective attribute even further to a certain limit for a limited period. For example feeding your dragon a magic damage shard would increase it's magic damage for 1 hour. You can feed it up to a certain amount of energy every hour. It would be able to buff dragons a bit more.
On the other hands maybe dragon cybergenetic engineering would be more viable. One can use dragon shards to increase his dragon physique up to a certain amount of energy or shards. Maybe one could even take it a step further and infuse certain parts of his dragon with shards. For example infuse his claws with magic resistance which one could add an extra effect to it.