Before internet, I would say Ray Franz would top the list. Ray was world famous, who hasn't heard of him in the 80s, famous apostate - evil slave.
WTS hates anyone that stands up to them. At present they hate internet that allows freedom of expression where they really can't do anything about it. It doesn't need to be jwfacts.com site or this forum but the fact that internet can't be controlled by them and allows dubs to have free access to anything they want behind closed doors, that's why they try so hard to program the minds of young ones to obey the masters at Crooklyn.
They hate higher forms of education because it not only keeps dubs from slaving for the cult but also helps them develop an ability to think and question which leads many if not most to leave the cult.
I suppose it's possible that wts spies on apostate sites but more likely they hire external companies (probably for copyright infringements) to do this so that dubs no matter how strong don't end up learning the TATT and possibly creating a bigger problem for them from within. Imagine having Bethel techs having a division to spy on here and the spy actually realized that wts is a fraud! What kind of liability wts would have on their hands with one of their techs being able to retrieve any info from them as they exit?
So I doubt that in today's world wts actually has top individuals that they hate but rather venues that allow dubs to learn TATT
No doubt, some heavy weights know of Barbra, Ray and others but most of this knowledge is probably from second hand sources. From elders telling COs, DOs... about what they've learned from the ones they've DF for apostasy during jc or from letters of DA. There may be few elders who actually visit apostate sites out of curiosity or out of stupidity thinking they can change others minds but many of these ones quit rather quickly or they realize that they've been conned and within time become exJWs themselves.