New Characters or Pre-Existing?

I really enjoy Star Wars Legends. I believe there is a lot of good material in Legends, enough so to make plenty of films, TV shows, video games and more. So when Disney bought Star Wars, I was excited to see all the new content that would hopefully honor what came before as well as create something different that we had not seen previously.

Well, we all know that TFA was meant to reel people in with nostalgia for the OT, and despite that it was a competent film with new ideas that I was intrigued to see be developed as time went on. Although as time went on, with the release of Rogue One, TLJ, and more episodes of Rebels and The Clone Wars, I started to notice something. Now don't get me wrong, all of them are fairly enjoyable and interesting films and TV Shows, but some of the characters reminded me of ones that already existed.

That being said, I ask this question: should new characters be created if there are known or Legends characters that can already fill the intended purpose the new character was meant to fill?

What if General Hux was Admiral Thrawn? What if instead of Ezra Bridger we had Galen Marek? Swap Kanan Jarrus for Quinlan Vos? Have Kyle Katarn and Jan Ors in Rogue One? Instead of Kanjiklub we see Black Sun?

Using pre-existing characters has worked - Thrawn in Rebels and Saw Gerrera in Rogue One are examples. I guess my main complaint is that some of the newer characters aren't written very well, and that if you utilized pre-existing characters, it would be easier for the writers and the audience to understand what those characters are "about."

I do realize that new characters keep things, well, new. A new character has infinite potential, and can play off of other characters and story elements in interesting ways. Kylo Ren and Rey are wonderful, clearly defined characters that work well together and separate. The writers of TFA could have used Jacen and Jaina Solo, but they took a risk and it paid off.

All in all, there are benefits to writing characters in the SW universe, and there are consequences. On one hand, there are limitations, but on the other hand, there aren't limitations. At the end of the day, it all depends on how the character is used - effectively or not.

That's my spiel. Questions? Comments? Concerns?

tldr; should new characters be made if Legends characters that work exist?