Hello my fellow Symmetry Sis and Balance Bros!

Any recs on changes for this 5th 4th-level spell (available to Druids, Rangers sorcerers (storm) and clerics (tempest):

You gather ambient electricity around you, which temporarily lets you attack with lightning speed. As part of the casting, you move instantly 30 feet in a straight line. This movement does not provoke opportunity attacks, nor does it count as the normal movement on your turn. Choose up to three creatures directly in your path. Each target must make a Dexterity saving throw. On a fail, the target takes takes 2d6 thunder damage and is thrown 10 feet in a direction chosen by you. If the creature fails the save by five more, they are also knocked prone. On a save, the target takes half damage and is not thrown or knocked prone.

Additionally, make a melee spell attack against each target. On a hit, the target also takes 2d8 lightning damage. If you use a weapon not worth at least 1 SP, such as arcane weapons created by flame blade, shadow blade, etc., you do not stack damage. Instead, your attack simply delivers the magic weapon's damage.

For example, if you use a second-level shadow blade as part of the casting of this spell, each melee spell attack would deal 2d8 psychic damage on a hit, as indicated by the shadow blade spell.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, increase your speed by 5 feet or each spell slot level above 4th. The spell deals an additional 1d6 thunder damage for each slot level above 4th.

* - (a melee weapon worth at least 5 sp or one created by a spell)* 

EDIT: Thanks to IamSposta for the catch and suggestions!

You say it's a 5th-level spell? Then here’s my suggestion:

You gather ambient electricity around you, which temporarily lets you attack with lightning speed. As part of the casting, you move instantly 30 feet in a straight line. This movement does not provoke opportunity attacks, nor does it count as the normal movement on your turn. Choose up to three creatures directly in your path. Make a melee spell attack against each creature. On a hit, the target takes 2d8 lightning damage. Each target must then make a Dexterity saving throw. On a failed save, the target takes takes an additional 2d6 thunder damage and is thrown 10 feet in any horizontal direction chosen by you you choose, but not with enough force to do any additional damage. If the creature fails the save by five or more, they are also knocked prone. On a successfull save, the target takes half damage and is not thrown or knocked prone.

Additionally, make a melee spell attack against each target. On a hit, the target also takes 2d8 lightning damage. If you use a weapon not worth at least 1 SP, such as arcane weapons created by flame blade, shadow blade, etc., you do not stack damage. Instead, your attack simply delivers the magic weapon's damage.

For example, if you use a second-level shadow blade as part of the casting of this spell, each melee spell attack would deal 2d8 psychic damage on a hit, as indicated by the shadow bladespell.

At Higher Levels. When you cast this spell using a spell slot of 5th 6th level or higher, increase your speed by 5 feet, and the spell deals an additional 1d6 Thunder damage for each spell slot level above 4th 5th. The spell deals an additional 1d6 thunder damage for each slot level above 4th.

* - (a melee weapon worth at least 5 sp or one created by a spell)

Quote from IamSposta >>

You say it's a 5th-level spell? 

Sorry, it's a 4th level spell. It's like a teenager version of Steel Wind Strike, which is 5th level. Thanks for your wording corrections and your suggestions. You think letting someone use Shadow Blade as their weapon for this is a bit too much? I figure, since it's available to mostly half-casters, they're not getting this spell until 13th level and an multiclasser would need 3 levels in sorcerer or wizard to gain access to shadow blade. That would make them 17th level. Would a paladin use 2 spell slots to make this work at higher than the spell's base damage? Is there an exploit I'm missing? Thanks again for the suggestions and discussion!

Not too much, just too complicated IMO. It didn’t add enough of anything to the experience of casting the spell that was worth all those additional caveats. But if you disagree then rack socks with it. I’m just someone on the internet after all. But my suggestion is to keep it simple, especially at an even lower level. Look at it this way, my revised version is still twice as complicated as steel wind strike.

Quote from IamSposta >>

Not too much, just too complicated IMO. It didn’t add enough of anything to the experience of casting the spell that was worth all those additional caveats. But if you disagree then rack socks with it. I’m just someone on the internet after all. But my suggestion is to keep it simple, especially at an even lower level. Look at it this way, my revised version is still twice as complicated as steel wind strike.

 
I guess I wanted to codify the ability to use something like Flame Blade with this spell. But you're right, I can just leave that bit out to make it read more simply.

And without that Material component, it leaves it to some perceptive players' interpretation to "exploit" this spell to their benefit. 

Thanks again!

Happy to help.

What “exploit” potential do you see that I don’t?

Oh, wait, I get it now what you were worried about. But worry not, because the damages wouldn’t stack anyway.

• For shadow blade it actually creates a tangible weapon that requires the Attack action to make melee weapon attacks.
• Flame blade grants its own special action just to use it.
• Your spell requires them to use the [Tooltip Not Found] action to cast it.

The only way do use two Actions in one turn would be to Action Surge, and you would have to do them independently.

What all of that stuff I chopped out added to your spell was that they could have replaced this spell’s lightning damage to use the fire/psychic damage from the other spell instead…. Problem then is you were adding the other spell’s higher level scaling in addition to yours for the thunder damage. You were accidentally doing more to combine those spells with yours than you were to separating them like you intended to. Make sense.