I'm sure this change will impact Legacies' storyline in a positive way. That's because Ryan Clarke's character has a huge potential since he is the creator of "TRIAD" and son of malivore, therefore, Landon's brother. We could have another great brother bond, which would recall TVD and TO.

Another reason why he would be a great addition is his dynamic with all the characters, especially Landon, Hope and Lizzie, wich is really interesting and captivating. Another thing that would be interesting is to explore his relationship with Hope. We've already seen multiple times that they can relate to each other in ways no one else can and their relationship had a great development over time. 

Now that the TRIAD's storyline is apparently being explored, and Aurora used a weapon that he created, he would be a great addition since he could use his notions to help.

A lot of fans are really attached to his character and would like to be able to see him more frequently and to know more about his past and possibly future great storylines.