Need help designing a Spellshaper class

[HiroGainsborough]

I want to build a class for Spellshapers from Magic: the Gathering and I'd like some ideas from people who are more experienced than I am at this sort of thing. Here's a description of them from MTG Wiki:

"Spellshapers are amongst the most narrowly focused spellcasters. They are salesmen of magical spells and devote themselves to perfecting a single spell or selection of spells, relying on their mastery of their focus to make up for their lack of versatility. In all other respects they are similar to wizards, clerics and druids."

Basically, I want it to be a Spellcasting class that focuses on making one single spell as good as it can be.

Any ideas are appreciated.

[avr]

Any spellcaster taking one or both of the metamagic reduction traits on a single spell and a lot of metamagic feats could do.

A prepared spellcaster might find it useful to aim for preferred spell.

A spell specialist archetype arcanist gets a couple of options but they aren't necessarily useful one.

Several sorcerer bloodlines specialise in a group of spells - fey sorcerers for enchantments for example.