He sounded like a complicated individual, not to mention controversial. I never met him personally. I've only ever been to one Star Trek convention in my life, which it seems is where most fans have met Arnold.
For some he is disliked (I hesitate to use the word hated because, after all, we are talking about a fictional franchise, though he made life difficult for some). He said he was basically acting under orders. I don't know enough about the inner workings of Star Trek to say if that is actually true or not. But suffice it to say, he made some people's lives more difficult, especially in regards to tie-ins. At the very least he stepped on a lot of toes and after Roddenberry's death he seemed to have been quickly shown the exit.
And for some it sounds like he could be a nice guy, from some comments I've read about him, later in life he could be very informative and open with fans. He sounded like someone that liked to share his love of Star Trek.
So perhaps, like most of us who walk the Earth, he was neither hero nor villain. Just someone who made some mistakes along the journey. Rest in Peace.