Well, the timeline does fit with the creation of DS9 circa 1991 - which went in a whole direction viewed as very un-Gene Roddenberry and un-Star Trek by some fans because of where it went.
GR had several edicts that a lot of writers didn't like (Ronald D. Moore has been relatively vocal about them) but had to work with that fit his vision of Trek - or at least the one he was having that week due to his ever revisionist nature - so I think there's some slight merit in the darkness claim. Just a skoosh.
The terrorism thing? Yeah, not sure where he was on that at all.
'If the Apocalypse starts, beep me!' - Buffy Summers
'The sky's the limit.....' Jean-Luc Picard, 'All Good Things'
courtesy of Saquist