-Don`t use Dragons who still use the old math. Did it once when I was new to 4E and the encounter was as thrilling as watching grass grow.
-Give your dragon unique powers and build their horde into the encounters. Dragons-by-the-book don`t pull off a lot of tricks besides roasting everyone in a defined blast and piercing their claws into the fighters. Especialy low-level dragons to me seem boring as hell.
When I put my group against a young iron Dragon his horde was completely filled with mountains of copper coins. Whenever the dragon unleashed his fury in a breath attack the copper coins created a lightning echo, unloading onto the first target to touch them/walk on the square with a coin mountain on it. Evil GMs gotta love conductive metals

And on a positive note, you also have a use for all the pennies eating up space in your purse
And like in any good bossfight include some interactive terrain for the solo and your players to abuse. Dragons are rather weak on the forced movement-side of powers, but since you`re the GM you`re free to modell them to your liking, right?
Other than that, my players frequently skin dragons, take their claws or chop off their heads. Last time we played they even took the eggs of one with them. The sorcerer in my group hopes to get the hatchlings trained to be his apprentices someday... And I want to best honest, I`m fine with my players looting solo monsters. Being a hero is about gathering trophies, for what proof of your deeds would you have, if it were not for those trophies?
Every action has its consequences and slaying a dragon should never be easy but always feel rewarding. Notorious dragon slayers normally get slain by more powerful dragons or their hired blades. Dragon slayers get noticed for their deeds and spreading cash around might well attract thieves and bandits. And never forget about the humanoid allies of a dragon and their networks. And the whole trophy-gathering has some roleplaying hooks as well. Maybe the reputation of the heroes inspires bards to sing of their deeds or maybe a young, galant, yet cowardly noble asks for a piece of the treasure to finally win the heart of a loved one who despises him for his cowardice.
And if you are worried about the item power level, it is in your best intentions to let it scale. My group killed a dragon who was level 6, the armor the paladin is going to get forged is level 8 and she is not going to receive it before level 6/7. Forging weapons and armor takes time and finding a smith who will work on fresh, raw dragon scales is always worth a skill challenge. And it is within your rights as a DM to reduce the treasury found in his horde by a reasonable amount to make sure the heros don`t gain too much benefit from slaying dragons.
And btw, if your dragons look and end like the one on the picture, you know you`re doing it wrong
