This is GREATLY unbalanced, especially at the beginning of the game before the Karma is payed of:
True Drakes maximum Edge becomes 8.
This is the equivalent for being human and having the positive quality Lucky, but it works for other Metatypes too exeeding their usual limits by 2. It's not a major issue, but still it's a benefit that is not available to any other character and combined with Lucky you can get to 9 Edge...
Since Dracoform is their natural form, all True Drakes are considered to have the drake power "Dracoform mastery" from the get-go.
This is an major issue.
In contrast to conventional Drakes they do not need to pay of the Karma before accessing the Drake powers. Effectively you lend the player 75 to 125 Karma that can be payed of later. You do not need to pay all the Karma at character generation and there is no minimum you need to pay at that time so depending on the GM you only need to pay 1 Karma or no Karma at all to get all the (non-optional) benefits of a Drake with Drakoform Mastery.
True Drakes get the following optional drake powers for their dracoform: Magical Guard (9 Karma), Regeneration (19 Karma) and their limit for "Improved Natural Armor" is their Magic +2 instead of just their Magic.
Adding more options that are usually only available to infected (they are unavailable even to shapeshifters) and improving on limits for drakes does not make your house rule more balanced.
Infected "pay" for their abilities by being constantly forced to hide what they are and getting a allergy that can be truely troublesome. A True Drake only needs to hide from bounty hunters and people with astral perception as long as it does not choose to reveal it's true form.
Especially Regeneration is a incredibly powerful Critter power and there is no Allergy to prevent regeneration.
Summing up you provide an option that is better than a conventional Drake and better than any non-Drake with small exceptions regarding Bodyware, something that is pretty unattractive to conventional Drakes anyway.
Consider a Western True Form Drake Unarmed Combat Adept. You could build the same character as a normal adept an and then add the True Form Drake without paying a single Karma point at character creation as long as you do not use Bodyware.
Just calculate the equivalent in power points for the "free" powers the True Drake gets:
- KON+2, STR+2: 4 PP
- (Mystic) Hardened Armor 2:
This is equivalent to rating 5 Mystic Armor (1 Auto-Success = 3 dice) = 2.5 PP
- Elemental Attack: Since this allows for ranged attacks and has a higher AP I'd consider this equivalent to Elemental Body: 1 PP
- Dual Natured: Free Astral Perception: 1 PP
- Vestigal Wings: Light Body 2: 0.5 PP
Summing up: 9 PP with the limitation that those points are only available in your true form...
After paying of your Karma debt you've got the option of becomming an unkillable tank by buying Regeneration and maxing out the hardened armor. At worst you become a 13 KON/12 Hardened Armor Troll-Drake by the time you reach ~250 Karma. Add Mystic Armor 6 and conventional 14 Armor (even as Critter armor this would be allowed) to complete the desaster:
Soak: 45 + 6 auto-successes
Healed Damage/Combat turn (Stun/Physical or overflow): 13 + successes with a pool of 19 dice
Physical Monitor: 15
Try killing that thing with anything but huge amounts of explosives or a Manipulation spell... You could certainly achieve such a soak pool with conventional drakes, but those usually keep the damage during a fight...
With point buy it would be more balanced especially since meta types with extreme Attributes tend to be expensive. However Regeneration should still be of the table. Regeneration is too strong without a Allergy that opponents could exploit and it was removed from shapeshifters too. Dragons don't have this power either so there's little that justifies allowing it.
Improved essence without the possibility of implanting bodyware seems to make little difference however there are some rules this interacts with. But I'm not aware of any game-breaking combos. With Uncanny Healer (Chrome Flesh) you get additional +2 for natural healing but this isn't really a game-breaker. Blood Crystals (Frobidden Arcana) also use Essence but playing a Blood Mage requires permission of the GM anyways...
There's one thing you need to establish a rule for though: What happens if the True Drake's MAG attribute is reduced to 0? Conventional drakes simply cannot use their drake powers anymore but what happens to a True Drake?
However if you spend 125 of 800 Karma on buying True Dracoform you probably get a less versatile character. If Karma-Buy and Sum-To-Ten/Priorities are options at your table, expect your values in human form to be worse than those of any comparable build in Sum-To-Ten.