It seems his feelings are still pretty raw, which is understandable considering the issues surrounding the movie before it even released and then the final, chopped up and convoluted product we ended up with.
As far as sci-fi films go, I suppose I can agree that the first film would seem like "lightning in a bottle". But it's also obvious that Predator could have easily gone the other way if not for the competence of the director who took a somewhat grounded approach to a story that pushes the limits of realism. Plus the decision to redesign the creature helped make it all the more memorable and stand out among other sci-fi films.
The Predator had a lot of potential for being a better received entry had they refocused certain characters and story elements. They should have gone with the Bad Blood story line, rather than the genetically modified 10 foot Predator who ultimately seeks out a child with Asperger's.