Path of Radiance was the introduction to the Western world on a console, so the difficulty level was set lower than in Japan, hence the offset. If you have beat Radiant Dawn on normal mode, well then Path of Radiance hard mode is similar in difficulty. Ashnard moves, but you just have to keep all your units out of range besides Ike, who has to solo either way; this time without supports.
I have beat Path of Radiance on hard mode, but in currently working through Radiant Dawn on hard, I'm having a much more difficult time. In the past I gave up twice on Part 1 Ch 5. Jill kept dying before I could get anyone up there to protect herself from the mages; that or I lost units in the rush to get there. This time however, I finally got through it by giving up the idea that I can keep every unit alive. I lost Meg and Aran in 1-4 and Edward, Leonardo and Ilyana in 1-5. Not detrimental losses.
Too any newcomers to the series, I wouldn't let the difficulty turn you off. There is an easy mode with in game guides. The difficulty of the harder modes adds to the replayability. It requires some thought but its also turn-based, so you can take as much time as you need to sort things out. I also don't think it appeals to just a "hardcore" gamer, as I don't see myself as one. I play in the evenings for about an hour before bed, sit back, dose off to the music, wake up a few minutes later and keep playing without missing anything.