It would be nice if

1. There where more effects since effects are nice. (Including one to remove particles) (And one to remove FOV Changes!) Also, those two shouldn't be dependent on other ones having to have it!
2. An ingredient that allows you to add in one ingredient that doesn't match maybe?
3. Just more things in general to this already awesome mod! (I remember 1.6.x, and it's just gotten better, can't wait for what's next!)

4. An advanced way to mix effects, and you can only combine 2 ingredients, but they will keep all their effects (Just a suggestion!)

This is, however, just a suggestion. It's your mod, and you can chose what to do with it!

1 - I am happy to hear what other effects and related ingredients you would like to get included. I am pretty busy with other stuff, so if you're willing to take a stab at this that would be very helpful.
You should be seeing no particles already as that's one of the features of Reliquary potions. I can look into FOV change for speed/slowness (though I tend to like it for slowness as that's negative effect)
2. I am not very fond of breaking the rule of two ingredients having to have the same effect for that to apply. There's a huge number of combinations so it shouldn't be difficult to always find something that's doable to get effect(s) you like. The same applies to 4.
I still have elsewhere flask item skeleton in the code base (something Xeno planned on adding) and will probably add that. This way you will be able to mix any potions into one flask. However not sure about the mechanics of mixing those. Not sure I want to make it an easy combine potions with flask in crafting table. Again any thoughts on that are welcome.

1. I Agree for slowness!
2. Ok, makes sense!

(I understand the basics of java, but I'm waiting to lean about modding minecraft for 1.13! (I was about to start when I heard all of the changes they where doing, and I though: "Why lean it, it it's going to be completely altered soon)) So, after 1.13, I'll see what I can do!

Thanks!