So, on this idea of "Dredge as Combo," let me explain the counter-point.
In Magic, and especially Type I (and later Vintage), Combo is som ething of a term of art. In a precise sense, we would think of combo decks as decks like Flash, Worldgorger Dragon, Trix, or Cephalid Breakfast: decks that are literally trying to assemble 2-3 combo parts for an explosive synergy that either generates tremendous card advantage, mana advantage, or directly ends the game: like Animate Dead on Worldgorger Dragon or Flash discarding Protean Hulk, or Donating Illusions of Grandeur. Those are combo decks.
Unfortunately, in our vernacular, the term "combo" also applies to generalized strategies that don't actually seek to sequence specific card interactions. So, decks that just play 9 spells, whichever way possible, and cast Tendrils of Agony are considered "combo decks." This is because the term was used in the early and middle years of the game to decks like Prosperity and Academy, etc. Modern Long (just as original Long) belongs in this vein and this school, but it is not a combo deck in the narrow sense of Flash or Dragon or Trix.
If we go to the very early years of the game, both the Animate Artifact, Instill Energy, Time Vault deck was a combo deck, but it was the combo deck in the specific sense of the former. As was Stasis + Kismet + Time Elemental. Yet, probably, 30 Lotus, 20 Timetwister, 1 Braingyser/Fireball deck was not. Yet, that latter deck is the direct ancestor of the Long school.
Dredge is not a combo deck in the sense of being either in the Long school or a specific 2-3 card interaction. Rather, it is a generalized strategy that appears combo-like because of its power and speed. It's very much in the mold of Mark Chalice's The Machine. Instead of Narcomoebas, Mark Chalices deck used Tetravus tokens. Instead of Dread Return, it used Hell's Caretaker and Animate Dead.
Mark Chalices deck is the direct ancestor to Dredge. Both decks sought to put threats into play from zones other than one's hand. That's the fundamnetal principle of these decks. They also used Bazaar, although Chalice's deck also used Jalum Tome. In my book project, I will figure out a better way to describe this school, but at the moment I'd argue it has these tenets:
* Seeks to deploy threats from untraditional zones, such as the graveyard
* Is often graveyard-centric, with reanimation spells or self-reanimating or generating threats (i.e. Ashen Ghoul, Ichorid, Bridge)
* Efficient & powerful disruption, but usually black disruption in the form of discard, although not always, to protect its kill
* Includes ways to discard cards from one's hand (e.g. Bazaar, Jalum Tome, Careful Study, Read the Runes, etc).
If I were re-writing Hahn's schools of magic with this school, those are the basic contours I would decribe. Broad enough to include early Reanimator decks, like the Machine, and middle-aged variants, like Dragon, but also modern versions, like Dredge.
Before you think Dredge is something else, let me offer two more points:
1) I played the first major Dredge deck to an SCG Top 8, and this was before Future Sight was printed, which allowed Dredge to go entirely manaless. I made Top 4 with this deck:
http://www.starcitygames.com/magic/vintage/11558_Monster_Mash_Dredging_Up_Aggro_In_Vintage.htmlCreatures (21)
3 Ashen Ghoul
4 Golgari Grave-Troll
2 Golgari Thug
4 Ichorid
4 Putrid Imp
4 Stinkweed Imp
Lands (13)
4 Bazaar of Baghdad
4 City of Brass
4 Gemstone Mine
1 Strip Mine
Spells (26)
1 Black Lotus
4 Chalice of the Void
1 Chrome Mox
1 Lotus Petal
1 Mox Jet
1 Mox Sapphire
1 Ancestral Recall
4 Brainstorm
1 Crop Rotation
1 Vampiric Tutor
4 Cabal Therapy
4 Careful Study
1 Imperial Seal
1 Time Walk
Sideboard
4 Null Rod
4 Pithing Needle
4 Chain of Vapor
3 Darkblast
This is not a combo deck. If you see this deck as the pre-Future Sight dredge deck, then I think it shows that I'm right, and illustrates my second point:
2) Which is that modern Vintage decks from EVERY school could be called "Combo decks." Control deck use Time Vault combo or Salvagers or something else broken. Etc. Vintage decks have evolved to the point where every one of the schools of Magic seems to have the capacity of for a combo finish. Even Workshops have Forgemaster. That doesn't make them combo decks. It just makes them explosive or really high powered.
Bottom Line: Dredge isn't a combo deck: it's simply the most highly powered, modern iteration/example of its school. And, like all such modern representatives of its school, has such a high power level that it appears combo-like in "folk taxonomy" or heuristics of Vintage, but it's not.
