Hi!
I just came back after a long time off and the graphical improvements since that time have made it difficult, especially when tanking or melee, to see much of anything.
It turns into a rainbow blur on most fights and makes encounters more difficult because you literally can’t see anything.
I would really love an option to show only my own and enemy spell effects.
There’s already been an option for that.
Blizz isn’t going to lower it to yourself and enemies. Otherwise you won’t stand in ally healing rain or efflorescence.
How will you stand in Barrier, AMZ, Spirit Link ?
Stand in Healing Rain ?
There’s already an option to reduce the visual clutter, but you can’t just go and disable every other player’s spell effects, for your own good.
There’s already an option in the menu to turn down extra spell effects. You need to be able to see other player’s spells, as some of the beneficial ones require you to stand in certain spots or provide a visual effect to know you have it (like bark skin surrounding you in vines).
Others have pointed out some good points.
But I’d like to add one extra.
The whole point of being melee is that you’re in the thick of it. It’s supposed to be chaotic.
If you really don’t like it, I’d suggest ranged.
Then they need to limit it to beneficial spells of others… because quite honestly it is getting to be way to much and has been for a long time. That and red used to be bad… Now it can be good, bad or ugly… green used to be good… now it can be good, bad or ugly. I no longer wish to dedicate the time or energy to remembering 36 specs different spell effects.
Hate to be that guy but as an example of what other successful MMOs are doing i’ll point out that FFXIV gives you both options. Anybody MMO savvy enough to go looking for that option to begin with is likely understands why self and enemy only effects can be dangerous but it’s nice to have the ability to choose.
I’d like to think people are smart enough that they don’t need things to be broken down to kindergarten level to know what is and isn’t ok to stand in.
So now you’re calling me stupid. Nice…
No I’m not. I’m saying people are smart enough to be able to learn what is good and bad, having to color-code things is unnecessary.
Keep these types of spells shown?
The mental gymnastics I went through to figure that one out. 
Which is already an option in game and this whole thread is useless then.
OP specifically asked to hide everything, I was pointing out why that’s a bad idea.
FFXIV does it just fine and they have aoe abilites that benefit you show while the option is toggled on.
Works great actually.
So does WoW.
Adjust Spell Density.
Enjoy.
and decreasing visual clutter is QoL upgrade.
During a raid I was leading once, I kept having several dps die to fire, over and over and over again.
It took me having to explain it to them like this, “If this were real life, would you stand in fire? No. The same goes for in game. If you see something bad, get out of it ASAP. No casting a spell, no more dps - get out of it.”
That was the only way I got it across to them. 
Dial up sounds
I’m pretty sure there is an option to reduce effects.
I think it’s also possible to turn off or lower certain effects beyond what the sliders allowed via console commands.
Turning off death effects is an example /console ffxDeath 0
And in the past /console spellEffectLevel 1 turned things way down.
No idea what kind of commands exist or work today. Or if they even exceed the values of the sliders anymore.
But the game has options to lower spell effects. Try that. Still not enough for you? Maybe go beyond the norm, and look into seeing if some console commands could be useful to you.