Core prestige class. How would this be built in 4E? And yes I know Sorceror is not out. Some of the perks were permanent effects that would now most likely be consider utility powers but now those are limited in duration. Also what could be a valid alternate for the stat increases?
I think it depends a bit on why you wanted to play a Dragon Disciple, but I'd basically lay it out as a Paragon Path or Epic Destiny, or even both (WotC didn't really make any secret about the idea that Paragon Paths were meant to replace Prestige Classes). Alternatively, you can reflavor magic items or feats that give similar types of bonuses. (My preference would be to reflavor the magic item creation Ritual to be a Draconic Initiation Ritual and give you powers of equivalent level magic items - including use of slots - when you put the components in).
Let's go through the class features and think about how to convert them:
Bonus Spells: this replaces normal spellcaster progression in 3.x, but in 4E a caster would still be gaining spells as normal for his levels. Essentially, 4E gives you this for free, though you could add one or more arcane attack powers to the PP or ED.
Natural Armor: Your character can take armor proficiency feats and "reflavor" them as natural scales (in my games, at least), using rituals that follow the magic item guidelines to improve them as you level. Or the Path could grant you an armor bonus of appropriate level.
Natural Attacks: Increase the damage die/proficiency bonus of the characters unarmed strikes as one of his Paragon Path features (not a power). (Leave aside the exact amount for now - it's okay to scale this depending on how many feats the character spends, basing it on weapons the character is proficient with). Let these be enchanted by rituals if you want.
Ability Boost: Increases to Strength, Con, and Int => greater HP, better attacks and defenses. You can represent these with damage bonuses, bonuses on Athletics and Endurance checks, more surges, increased surge value, and/or power(s) that let you heal yourself or gain temp hp. Alternatively, you take feats like Toughness and Skill Focus: Endurance to represent your Draconic Might.
Breath Weapon: Encounter/Daily attack power from PP/ED. Scale to the level you want it to appear at. Alternatively, reflavor an existing wizard power to match.
Blindsense: Utility power (or maybe even feature of an Epic Destiny - I don't have a good enough sense of epic-level 4E to balance this easily). Alternatively, you can take Skill Focus: Perception and we flavor it to be your improving Draconic Senses.
Wings: Depending on the level, this could be an Encounter or Daily ability allowing flight (one move action for Encounter, up to 5 minutes for Daily), or even a flat Fly speed (again, balancing epic-level features with precision isn't something I'm prepared to do right away). Alternatively, you perform a Ritual and pay a cost based on <insert magic item that allows flying here>, we flavor it as wings, and you can fly as well as that item can. Improves as you perform further rituals to match the effects of better items.
The Dragon Apotheosis is mostly dealt with by expanding on what's written above - more stat increases, more sensory ability (either power-based or reflavored feat/item based), immunities that 4E dragons don't have, resistance to breath weapon's damage type.
