Suggestions for things I would find useful:

1. The option to turn down, or off the battle music in settings. I usually listen to music while playing Sylestia, and the battle music usually disrupts what I'm listening to.

2. The ability to search for a specific thread based off the title. Whenever I have a question about something, I go to the FAQ section, but can never find the thread I'm looking for.

3. Maybe there could be a filter in the scale shop, or diamond shop to give the ability to change a pet's gender. (If there isn't already one) I often find that there are 2 pets I want to breed, then realize they are the same gender.

Edit:
Another suggestion: Wouldn't it be cool if we could create customs with our own art? Not just coloring it in, but drawing the whole thing ourselves. It's not my decision to make, but I would love that.

#1 and #3 already exist.

#1: Just look for a little speaker icon while in battle, and click it.

#3: Philter of Gender Swapping.

Okay, thank you!

Also, #2, forum / thread searches have also been requested multiple times (myself included). If memory serves, it was said that it's something they want to have in the future. So fingers crossed~ ^-^

For the last suggestion, there are sometimes contests in the forums during fests/events to create items or even a whole ensemble for the fest, and some of them actually get made ^^

Oh, Cool! Thank you for telling me :)