not really sure what your point is so maybe you can clarify: are you saying it's ok to have a separate type of warrant for terrorists?
"traditional warrant system" is not a legal term. FISA warrants are warrants. Highly problematic, but warrants.
You may be interested in reading about how even FISA felt the NSA overstepped:
https://www.vice.com/en_us/article/d7axey/this-is-the-secret...