Some of the champions in HoN were really interesting, probably my favorite part was some of the design concepts.
Example: The Puppet Master was a cool carry with interesting CC. I mained Ophelia, who was a jungler that micro'd units with their own individual spells and auras.
By less forgiving I'm assuming he means once you get behind it's hard to get it back. One power up spawns every 2 minutes randomly on either the left or right side of river that could give you things like double auto attack damage, full health, or even invisibility. Some champions were viable mid (or not) based on the merit of securing the power up.