Errrm, deadly dragons is good, but Resilient dragons i find is much better... reduces NPC damage etc
its on steamworkshop and nexus
http://skyrim.nexusmods.com/downloads/file.php?id=10591
DD is good but does too much and doesn't make it harder.
Resilient dragons gives dragons more health, making it longer and more epic fighting.... reduces damage NPC's do to dragons.. meaning no longer will a farmer/mudcrab/bear/wolf manage to kil la dragon.
plus DD is alot more buggy and problematic and i don't like some of the "added" extras in DD
Review from someone sums it up;
Endorsed!
I would like to reinforce the sentiment of some here. Please do NOT add anything over the top to this mod. Just keep tweaking to make dragon fights more epic and challengening. The reason I uninstalled DD is because of all those 1337 spells, armor sets, all those strange named dragons that were never in the game to start with. Way too much of an overhaul. This mod makes them very challengening without injecting a lot of new things into the game.
I wouldn't mind seeing dragons using more shouts other than their breathes. Also, the fear effect on NPC's is a fantastic idea, the more refined and polished that becomes, the better. Old wummenz shouldn't be pulling out their kitchen knife and charge into dragons, nor should the avarage farmer Joe. 
Thank you very much for this mod, Kenomica! And again, please keep it simple, don't add over the top stuffs.