weak excuses about adding viera

[Kit-Kat]

That was the Dev given opinion during F.A.T.E Tokyo
新種族の構想当初はやはりヴィエラが第一候補だったという。ヴィエラは国内でも海外でも人気が高く、求める声が多かったがすでに実装されているミコッテとイメージが被るなどの苦悩があったようだ。
"Originally when planning a new race Viera was the first candidate. Viera is popular both in Japan and overseas and there were many requests, but it was too similar to miqo'te" is pretty much what they said.

They were talking from when they first planned in adding a new race (3.0). The reason they didn't add Viera for 4.0 is the work part, and not because it would look like a miqo'te. I'm pretty sure if they ever decide to make a new race, it would be Viera.