Increases damage done by dragon breaths by 50% to 150% and boosts the health of dragons by 3x-10x.  The goal is so that those with modded games or stronger characters have dragons that are still apex predators instead of toys for random giants to play with.  This is a first-pass, so game balance may be slightly out of whack at player levels below 30 or above 50.

I suggest a mid-20s character, with 30-50% fire resist, and a bow capable of 50-60 damage along with 75-100 arrows for the first dragon battle outside of Whiterun.  I'm not sure how suitable this would be for a level 10-15 character with little to no resists against the breath attacks.  Plan on packing health and resist potions, and possibly marksman or other damage output increasing potions.  By my mid-30s, I usually have a bow that does 80-100 damage, ebony arrows (20 dam), plus potions that increase bow damage by 80%, plus resists of around 70-80%.  

Required DLC:

You must have both Dawnguard and Dragonborn DLC installed and active in your load order.

Dragon Health/Level Changes:

Note: The game use a base health offset, then adds a bit of health as the level changes.  So a dragon that has 3000 at level 10 might have 3300-3600 at level 40 (assuming that it is still in the spawn lists at that level).

Dragon:
- Health base increased from 300 to 3000
- Level range expanded from 10-10 to 10-40 (1.1x player)

Bleak Falls Dragon:
- Health base increased from 0 to 2500
- Level range expanded from 20-20 to 20-30 (1.1x player)

Blood Dragons:
- Health base changed from 700 to 4000
- Level range expanded from 20-20 to 20-50 (1.1x player)

Frost Dragons:
- Health base increased from 1022 to 5000
- Level range changed from 30-30 to 30-60 (1.1x player)

Elder Dragons:
- Health base changed from 1300 to 6500
- Level range changed from 40-40 to 40-60 (1.1x)

Ancient Dragons:
- Health base changed from 2000 to 8000
- Level range changed from 50-50 to 50-75 (1.1x)

Serpentine Dragons:
- Health base changed from 2400 to 10000
- Level range changed from 58-58 to 58-85 (1.1x)

Revered Dragons:
- Health base changed from 2300 to 11000
- Level range changed from 62-62 to 62-100 (1.1x)

Legendary Dragons:
- Health base changed from 2800 to 14000
- Level range changed from 75-75 to 75-100 (1.1x)

Alduin:
- Health changed from 1500-17 00 base to 15000-18000
- Base version, level changed from 10-100 to 40-100
- MQ304 version, level changed from 20-100 to 60-100

Dragon Attack Changes:

Breath attacks:
- Fire increased by about 3x-4x
- Frost increased by about 3x-4x, additional slow at upper levels
- Drain vitality boosted by about 2x