That looks like a fun list! I think I'll drum up a dragon list pretty soon as well. I would make a few changes on equipment, though.
Dreadlord: Doesn't need Armor of Darkness on a mount. Full Mundane + Mount gives a 2+ armor in combat, 1+ against ranged. I would go with either Crimson Death or Caledor's Bane. As previously mentioned, Crimson Death gives you the same S6 attacks at the cost of 1 armor while in combat; you still get the shield bonus against ranged. I'd giving your Black Guard Champ the CD, though, so Caledor's Bane would get my vote.
Master: Armor of Eternal Servitude + Dragonbane Gem gives better protection and is cheaper than the Armor of Destiny. Pick up a Beastman's Scourge for the +1 attack and Armor Piercing, a steal at 6 points. Alternatively, if you find your opponents don't hit your
BSB with flaming attacks, you can pick up the Sword of Might for S5 attacks.
Sorceress 1: I don't feel the Lifetaker is worth its points on a stationary Sorceress, you have plenty of other shooting with all those Crossbowmen and it doesn't put out 2.5 Crossbowmen worth of shots and wounds. Actually, after to-hit modifiers and wounding it probably does put out slightly better damage than two Crossbowmen, but not the additional two wounds in your unit.
Aside from this, dropping this and the Ring in my next suggestion opens up points elsewhere.
Sorceress 2: I'd drop the Ruby Ring of Ruin. A dice-free fireball is nice, but I'd prefer the points elsewhere.
On the subject of wizards, you didn't label your Lores. In 8th edition this technically does have to be chosen prior to the game. Lucky for us, there are a few lores that are very nice for a Lv.2 caster and synergize well with our Crossbows. Lore of Metal has a nice anti-armor Signature spell in addition to general armor lowering and that one +1 to-hit spell. Lore of Fire's Flaming Sword spell makes our Crossbows very scary: +1 to wound and flaming means you are wounding HPAs on a 5+ with Flaming Bolts, good stuff! Our own Dark Magic is a great utility lore as well with a good spectrum of spells with low casting costs. Lore of Shadow is very nice overall, but I prefer it on Lv.4's since they get more spells to choose from and get the +2 to cast boost to help with higher casting costs.
Spearmen: These guys are fine.
Crossbows: They don't need a Champion; an additional 10pts for +1
BS on four shots is not worth it. What may be worth it, depending on the missions, is picking up Standards for them. It also helps them stick around if something gets into combat with them. Always keep the Musician, it is incredibly frustrating to not have quick reform sometimes.
Harpies: Not a bad way to spend some points and can be handy in screening your Dragon, war machine hunting, or suicidal attacks on naked wizards. I'd prefer to sink their points into another unit of Shades, but both are fine and I know you mentioned these being your available models.
Cold One Knights: They look fine. The Musician can be dropped for points, but sometimes the quick reform is very handy.
Shades: I'd personally get another set of these guys as they are nice war machine hunters and nice distractions. With a little tweaking you have points for additional hand weapons, definitely worth the points when available.
Black Guard: I'd pick up the Banner of Murder or Flaming Banner, depending on what you expect to fight. Banner of Murder tends to provide the better overall bonus and helps chew through high armor saves like Chaos Warriors. Of course, I wouldn't recommend taking on a block of Warriors on their own, but as a combo charge with a Hydra or tossing in a Hex such as Word of Pain (love that spell!) you could come out on top. If you are bringing the Champion, I'd pick up the Crimson Death. His three attacks at S6 really help mitigate the bane of Black Guard: high armor and high toughness. This is why I would put Caledor's Bane on the Dreadlord.
Hydra: No complaints with a Hydra! I wouldn't call double Hydra cheesy, but we've had plenty of those conversations!
Besides, you have the points elsewhere.
What do you think about this?
Dreadlord - Dragon, Caledor's Bane, Pendant of Khaeleth, Full Mundane - 545
Master -
BSB, Armor of Eternal Servitude, Dragonbane Gem, Beastmaster Scourge, Sea Dragon Cloak, Shield - 157
Sorceress - Lv.2 Dark, Tome of Furion - 150
Sorceress - Lv.2 Fire (or Metal, or Shadow), Dispel Scroll - 160
24x Spearmen - Shields, Full Command - 183
20x Crossbowmen - Shields, Banner, Musician - 235
20x Crossbowmen - Shields, Banner, Musician - 235
5x Cold One Knights - Musician - 143
5x Shades - Additional Hand Weapon - 85
5x Shades - Additional Hand Weapon - 85
20x Black Guard - Crimson Death, Banner of Murder, Full Command - 345
War Hydra - 175
Total - 2498
You mentioned that what you have listed are your models, so if you drop the extra set of Shades (85pts) you could pick up your five Harpies and still have thirty points to play with (Ruby Ring, Lifetaker, etc).
