As you say, the Denizen fantasy and sci-fi figures have been around for quite a long while and, while the look of the figures is still fairly contemporary, figure sizes have marched on and upwards, away from the Denizen classic 25.
The rescale does give them a more modern height and the figures are still a good looking range for most generic games. As an aside, I noticed recently that someone rescaled the classic 25 'Spacefarers' figures to a modern height - very nostalgic towards those, some of the first sci-fi minis I ever owned (Denizen were the 2nd range of sci-fi figures I bought from).