Magician Delphox

[Trooj]

So I'm just starting out competitive and I was wondering would this set for Delphox make it a threat:

Ability: Magician
Item: Power Herb
Nature: Timid
EVs: HP: 4/ SpA: 252 / Speed: 252

- Solar Beam
- Fire Blast
- Psychic / Psyshock
- Wish

So this set would be for when I'm versing a Politoed or Milotic, I would start out with Solar Beam using power herb solar beam doesn't need to charge and takes the other Pokemon's item as a bonus with Magician. Fire Blast and Psychic would be stab moves and wish would be for health. Could this set threaten teams or do any damage?

 

[PMJ]

Solar Beam does not turn Delphox into a Water killer. Delphox isn't strong enough. Factoring in the rain, Psychic will almost always out-damage Solar Beam, and assuming 252 hp and 0 sdef on Milotic, Delphox can't even 2HKO with a Solar Beam/Psychic combination.

The problem is that everything you're gonna wanna use Solar Beam is either going to outspeed and KO you or tank the hit and KO you because Delphox just isn't strong enough.

 

[Chaos Jackal]

Delphox's only good aspect is its Speed, otherwise it's too weak to kill a bulky Water-type. Your best shot would be Choice Specs in a Sun team, but that doesn't use Magician and you still can't OHKO Milotic, maybe not even 2HKO, especially a Specially Defensive variant (which is a common Milotic set).
tl;dr As PMJ said, Delphox simply lacks the power to be a sweeper, or even a Water killer.

 

[Professor Palutena]

Why do you want Delphox to be your water type killer? Couldn't you accomplish that by using a Grass type?

 

[Grizzly]

Or Protean Greninja with Grass Knot.