The difficulty about this thread I believe is to seperate out what the real problem,if any, there are with the Dragons. I'm a major fan of dragons and have been for more years than most people where alive in this forum.
My age aside, there are a number of things that the dragons do that are nice:
a) Their look and feel is exactly as I expect it - Great job on the dragon designs. The visual is good, they move good, and the sound is great.

I like that the dragons actually HAVE a fly by attack.
c) I love that you can change the difficulty level - and on default setting - elder dragons are harder than basic dragons - all players are not he same. Those who complain on this factor should up the difficulty and think about what they would change and how it would be perceived in the game.
d) I think the balance off what they can do and dont do is good. They could be better but I think I would have to think about the impact to the game of many of the changes I suggest next and I know the designers must have struggled with many of them to come to the design they have now. They must have thought through all the things people have talked about in this forum before coming to the design they have today.
Less Positive feedback:
a) I have not encountered a dragon who properly uses their tail correctly. Tail swipes are a great addition to ground combat and a patch I would love to see. Tail swipes that might knock me off the top of a cliff would be excellent and deserving if I was in the position for such a thing.

The same comment on the dragons claws. I have seen few claw attacks that are effective. Undead archers can drop me in a single bow shot at this difficulty but the only dragon attack that has done that to me so far is the bite attack. I'd like to see them claw at me to push me back and do damage on the ground.
c) I have not encountered a dragon who will grab a character on the ground - fly them high and drop them. Probably because most players in the game would meet certain death if they were allowed to do so. Plus characters cant really GRAB on to the dragon's leg to prevent it. I think the game mechanic would be difficult to do...but being able to climb up on the dragon and attack from above would be a nice way for fighters to be able to really do what they can do. Dragging a character across the ground OR just doing a fly by claw attack - if the terrain allowed it would be nice.
d) A dragon that is heavily wounded - should try to run (if they cant fly) or fly away if they can. Again, I think this is because it would be frustrating to characters who almost kill one to have it fly away and for the game to maintain which dragon has how much damage in the world. It may work if they were allowed to run when almost dead - and until their health reached a point couldnt fly.. thus allowing characters to chase them down to deliver the killing blow. Knock the character back with a tail or claw and run on the ground until they can go airborn. Even if airborn is only for a short distance to land again and rest and heal before heading up again.
e) Older dragons should have more options and be scary. Are they? Maybe - that part is debatable depending on your difficulty level. Elder dragons have on more than once swallowed and spit me out in a single bite - killing me. Nice surprise. But other surprises would be nice - they are older for a reason - show us.
f) Lack of variety in their breath weapons was a disappointment. If I have 90% protection from fire, frost and shock - the breath weapon is a no opt. It doesnt even have blow back. I think if you stand directly in the breath of an elder dragon on the ground - it should push you back. It makes it hard to see but has no resistance and thats a patch I would love to see.
g) Uber dragons - I would like to see some dragons set in caves that are special - for example, a gold dragon high in a mountain cave off the path - that can give characters the highest level spells as a mage and if threatened turns into a dragon and kicks them out of the cave - fights at +1 difficulty level and has some special breath weapon. Also add some randomness on the dragons abilities - set a list of abilities and hand them out randomly to the random dragons - add some breath weapons like lightning, acid (to destroy armor), etc and possibly have a dragon that can cast spells.
I do agree with those who have stated in the forum about people trying the difficulty levels and then think of how they could change things that wouldnt completely frustrate a player. As a designer myself, I understand the designers difficulties on how hard it is to design dragons for a game like this.
For example:
1) A dragon who could run away when near death - could frustrate players each time they get near death but run away - failing to kill them - over and over.
2) Dragons who never land - would really frustrate players who dont have range weapons.
3) Dragons that can straff a character with claws could also be frustrating
4) Dragons who can pick up a character and drop them to their death would also be frustrating
Kudos to the designers for the way they are now because there is just something satifiying about killing a dragon (the only thing is that satisfaction gets stiffled by repeativeness and since you need dragon souls - I'm not sure how that can be fixed). Tough thoughts.