Regarding the trading of Djinn thing, I went through a few iterations of this Guardian in which you could trade the Djinn, and while it was cool and players enjoyed doing it, it also gave everyone way too optimal a setup for the game. It also just makes it so that everyone picks up all the Djinn at the start of the game, regardless of element, and trades them to get optimal setups. I know that's within the flavor of the original game, but it's a little too powerful for Arkham Horror.
Instead, the design approach I used was designating each element towards a particular facet of the game:
Earth - Combat effectiveness, tools against monsters, and general bonuses to being a monster fighter.
Fire - Self-improvement, energizing, effects that generally give you stronger abilities.
Wind - Evasiveness and trickery, provides free reign of movement and designed for running gates.
Water - Support and healing with some monster control, designed to help other investigators.
With that knowledge in mind and by removing the trading option on Djinn, what I wanted to encourage players to do was leave Djinn that would benefit certain players for them to pick up. Even though you don't know exactly what it does until you pick it up, you know more or less what it's tailored to do. Only pick up Djinn of a particular element if you are employing that facet of the game.
For the record, every time we've played Djinn, we only forgot a single Upkeep trigger. You can use a token or die to help keep track of it, but I didn't find it to be that problematic. So, now onto specifics:
Chasm - I guess I didn't think about that. Guess I'll change it to "Non-spawn monster". If that happens to include the Dunwich Horror, great. Otherwise, I think I'll leave that one be as a "crazy feature"
Corona - Well okay, that one is supposed to include the line "Doesn't refresh during upkeep". Don't know why it doesn't, but there ya go.
Flash - I'm just using the wording that most items of a similar nature use, like discardable weapons. Exhaust and discard is on all of them.
Fury - That's definitely a neat idea and I will think about it.
Brand - In this case it's a balance issue. You get to use Brand once, and you also get to use Flash once, but Brand is providing you with much more long term benefits as opposed to Flash where you get only one use. The balance here is that when you're done using Brand, it sits in your inventory and may prevent you from collecting further Djinn until you release it. Since Flash is so temporary, I figure it should at least save you the time of trying to release it.
Fugue - Look at Flash
Zephyr - Nope, the Speed +1 clause is separate from the exhaust effect, which means it always gives Speed +1.
Breeze - Technically no, since if you start your movement phase in an Other World, you just automatically move forward and aren't given any movement points. I don't know if the rules specifically lists it as "Reduced to 0 movement" or "Don't start with any Movement", but in either case Breeze was not intended to give you movement points in the other world. I think I might need to check the rules regardless since if you are assigned movement points at the start of movement, then I need to rework the way Breeze functions.
Gasp - I know that version of Gasp is a little out of date, but I'll assign the same solution as with Chasm. If it doesn't include the Dunwich Horror, I'm actually fine with it for the most part since the odds of both coming up in the same game are pretty low.
Sirocco - The effects are a little redundant, but they also have very different levels of power. One effect only comes up once in a while and carries with it no guarantees of success, while the other effect is super strong and guarantees success but at the cost of only being usable once. Sirocco is specifically designed to make people who are good at Evading even better at doing so. If you aren't good at evading, it's not going to make you much better.
Luff - That's a fair point.
Gust - In the case of Fury, I think it makes sense, but with Gust I wanted it to feel like building momentum. So, while I think the change to Fury is a good one, I also think I'd rather keep Gust as is.
Sleet - Yes, I agree the mobility granted on Sleet is ridiculous. It's also temporary. Sleet grants a total of 5 movement points over the course of an entire game, which is quite a bit, but also with minor restriction. It may sound crazy powerful, but there's a trick: It's not actually that great on a high speed character since they already dash across the map. It's amazing on a low speed character though, at least for a while. Additionally, the situation you mentioned doesn't work because it only tracks your first movement point spent. If you move from a street into a location, Sleet counts nothing for the turn.
Eddy - Regardless of how you word it, you're going to need to set one die aside for the roll. I just choose to say the first die so no one ever forgets to factor it in.
Looking at that picture, it is worth mention that some of those Djinn are out of date, and more importantly there's 3 Djinn missing from each element since I made even more