This card is actually quite balanced when you think about it, if you were in a situation to have to fractal and use this card on a creature (for example, if you were to change Giant frogs to fire, then fractal them) You would first of all need 3 sources of quanta, life quanta, constant source of fire quanta and a large number of aether quanta to fractal the frogs. A number of counters are available before the combo can start.
Evaluation:
I think the effect of the shard should only affect the one creature that the shard is used on. Reverse time is debatable but in my opinion is that it should affect effect of the shard. If there are no counters then the shard would be a bit overpowered don't you think? As mentioned in on of the posts before, the tactic where fractalling your opponent's dragons is a bit overpowered don't you think? Perhaps you could set the shard to only able to affect your own creatures. Other than those counters Overall I think if the card was implemented into the game, it wold be a bit underused as the combo would take too long to be effective and uses for the shards to be effective are limited. Perhaps try decreasing the cost to 2?