It totally has downsides. They are not severe downsides. But downsides non the less. For example There is a pretty significant arc when throwing the hammer that takes some getting used to for jumping and or moving targets. We also cannot simply spam hammers, we have to wait for the hammer to impact to gain a new one. I will admit that the damage reduction is pretty damned high during super. But there is perks on armor that may be increasing that as well. Ie "Increased armor when using a solar based subclass" I am unsure if that is only during the super or not. But that is dependent on how you build your character as well. If you do the sunspot build. You are way less mobile on account of having to be near a sunspot. So like I said, it does have down sides. Just not severe ones, that being said I have not touched the other subclasses just yet Ie storm caller, night stalker. So I cannot speak for there abilities. Other than the ability to stop supers with the bow.