The Disempower line isn't really useful when soloing. The amount of mana you spend and the spell slot you use isn't worth what you get back. The debuff is barely noticeable. This spell line is mostly useful on raid targets, where every little bit of debuff helps.
Blind DOES have a use case when soloing. I used Blind to solo Sirens in Cobalt Scar when I was level 52, and their spells had a good chance of landing. Getting Charmed by an Enchanter mob is a huge problem on a Shaman. All of your dots will become useless, and your pet will die. If the blinded monster is not next to a player or pet on it's hate list, the blind will act as a fear. This means caster mobs cannot cast spells while they are feared.
This is useful when fighting caster mobs in a large open area, where adds are not likely to occur. The requirement of being in a large open area limits the use cases, but it is a viable strategy when dealing with particularly nasty caster mobs. Even when the monster is unsnared, your main method of damage is Dots. It is annoying, but with SoW you can definitely keep up with a running mob, and dot it. If you are a troll, you can pair Blind with
https://wiki.project1999.com/Regent_Symbol_of_Innoruuk for a crappy version of fear kiting with snares. I did the fear kiting without a snare, so it is 100% doable on other races, but Trolls have a bit of an edge here. The only caveat is you cannot have a pet dealing damage to the mob while it is running, unlike regular fear kiting. You also need to pay close attention to your positioning. The mob will attack you and start casting spells if they happen to run by you.