I've never used Fredrick in game until recently. And that's only because I needed someone to keep Lissa safe in the opening chapters on hard. admittedly I only play on normal and now part way in hard. But in my normal chapters I used almost exclusively foot units with few mounts. On the other hand Seth was rather useful but he was put in the back seat when more units became stronger and I obtained Ephraim. In both games Joshua, Ephraim, and Ross where my hitmen in Stones. In Awakening my hitmen were Avatar, Gaius, Virion, and Vaike first gen. Second gen were Brady, Noire, Morgan, and Owain.

But as the big man wants so shall it be it's up to him in the end.