Well yes, you could have them breath anything you want.
But what happens if the dragon breaths his cone straight down from 50 feet? You have a 50 foot circle of devastation.
All my dragons have hover (I should have mentioned that, my bad) as their first feet.
Have you ever watched Reign of Fire? Or any movie with a dragon in it? Did any of those dragons have poor manueverability?
That being said, you do have to follow physics to some extent. However, I tend to make my dragons a bit more dexterous (thus manueverable) than the MM.
Remember and this is really important: MONSTERS IN THE MONSTER MANUAL ARE AT THEIR ABSOLUTELY BASE LEVEL...AS WEAK AS THEY CAN GET.
Which means you can boost them to whatever level you want. Your biggest problem with the encounter is it wasn't up to the EL of the party. With the standard CR and EL being set for 4 characters of a given level, you had more than twice! That significantly changes how an EL is calculated. You should have used a couple of adult dragons with 3 or 4 Raks or a dragon two or more age categories higher with a couple of Raks.
Below is a post I put into a CR thread. Read it and take it to heart:
Psions and Tarrasques and Balors, OH MY!
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There are multiple problems inherent in the system. One of the biggest is that too many people see the rules as absolutes, instead of guidelines. Pulling a creature out of the book by CR rating alone is not enough to prepare for an adventure as a DM. As Eric A. can attest, my encounters tend to be much more difficult than the CR would suggest. I'm a tough DM, and average about 1 PC death per play session; we'll not talk about friendly fire here. I'm also a generous DM and award XP appropriately. But a lucky strike or smart play from a PC can end almost any encounter quickly. Even when I build very difficult encounters, I always leave a way out, either to victory or to retreat. Whether the players find it, well, that's a different story.
This is how I personally do it:
1) KNOW YOUR PARTY! If you don't do this, the rest is pointless.
2) Pick a monster/creature/opponent because it fits the local, story, or scene, not because of it's CR rating. Any creature can be made weaker or stronger...enough to challenge any party.
3) Get to KNOW monsters and their abilities.
a) Some monsters have stupidly high CRs, because of one ability. What happens when you strip that ability, or change it to something less lethal? What's a Famine Spirit without its Vorpal Bite?
b) Some monsters have stupidly low CRs, because the DMG doesn't take into account its will to live (among other things). 20 orc warriors with 4 sergeants and one captain, armed with short bows, short spears and tower shields and fighting in turtles can give playes nightmares for weeks.
4) Get to know what abilities that your PCs have trouble with, and take advantage of it. In the same vein, throw some freebies at them to build their confidence.
5) It's important to understand that most players stumble on to monsters (and not the other way around). Most beasties will be prepared for adventurers. In fact, it's probably a favorite menu item! Oooh, roast wizard, rogue on a spit, boiled fighter, and cleric on the half shell, yummy! As the DM you should be playing the monsters as if they were your PCs (which in fact, they are).
6) Smart monsters retreat. In fact, the smarter the beastie, the more likely it will know it's outmatched, use its most lethal and/or favorite power to attempt to damage/kill a PC or two, and retreat to the hills. They may regroup, get reinforcements, buff themselves up, set up an ambush, etc. Very few intelligent creatures will fight to the death, unless they are backed into a corner, magically bound to do so, or protecting something (like a nest or young).
7) Monster use their magic items. Unless it's biologically impossible, less effective than it's natural weaponry, or the creature is not intelligent, make the players EARN their treasure. Nothing hurts so bad, is so valued, or brings bigger smiles, than pulling out the half used wand of fireballs that you pried from the dead Raksasha's hand...the one it used on you in its 20x20 bedroom (which it was immune to).
Remember, it's not the size of the dog in the fight, but the size of the fight in the dog.
DMing is an art, not a science. Don't try to turn it into one, or you'll suck all the fun out of the game. In fact, you'll probably feel like you're playing EverCrack.
