As a new player who started as blackguard, yeah it needs some work. God it was awful. Having the extra food requirements, especially while being new, was rough because you can't hunt anything effectively and there really wasn't a lot of wild plants. Not to mention I didn't know anything about cooking (not that I had pottery at the time anyway).
Really, I think there just needs to be more dungeon type encounters or fighting encounters. There is very little reason to make heavy armor in the first place, because the only time you're going to be fighting is temporal storms (or being ambushed by a wild animal, during which you probably don't want to be wearing heavy armor anyway because you would be exploring). If there were dungeons or places worth going to that had good loot it would make sense to have a fighting class, but currently I spend 99% of my time not fighting and therefore getting very little benefit from picking a class that is good at fighting, but I keep the downsides to that class all the time. Gimme some dragons to fight or something that are hoarding big resources, that way I can actually do what my class is supposed to do more frequently.
I don't really think being slower while wearing armor is a bad thing because it's rare that you should be wearing armor. To me armor is something that you have when you KNOW you're going to get in a fight. I don't mind being slower for that if the damage resistance is worth it, which it usually is. But having the blackguard armor movement speed be buffed would be nice. You wouldn't be exploring in plate armor still, but chainmail? That's doable.