It's a magical fantasy world in a video game for crying out loud. You know, a world where you can experience things that simply are not possible in real life? Are you really going to nit pick about armor being to heavy to jump in because it goes against the laws of physics in real life? Maybe it is just me, but something so trivial certainly is not going to take away from my immersion in this grand world they have obviously worked so hard to bring to us. I suppose to each their own, though.
The mere existence of magic in a fantasy world doesn't mean everyone is able to do everything effortlessly. And especially
because Larian has presumably put a lot of effort into creating a believable, detailed world, they should also pay attention to details like this one.
Even if we assume that by becoming a dragon knight, the well-trained human character gains superhuman strength and agility that he/she can use without spending mana, why should he/she
want to brag about his/her superhuman abilities with each and every jump? With a rogue-like approach to your character and when often relying on stealth, staying undetected or unnoticed, the show-style jumping is especially silly.
So yes, it's a detail, but no, it's not trivial.
