Thanks for the input from the MP front. I guess I look at it in terms of time investment to make the stones, and empower mages (since you do not have blood naturally anywhere). Taking a drain scale (since D2 just seems like 80 free points to me...) means that your only decent researcher is your pretender, and if you go astral he's also the only one able to forge anything interesting there, so where do you make the stones from? And how long does it take to set that up? One stone a turn for 20 turns gets you to some nice numbers, but the up front cost seems to be a hindrance in actually raiding/killing your neighbors.
I see this Machaka build as being highly mobile, and very good at engaging in skirmishes, however, it can also pull its elements together quite quickly for a concentrated effect (unless the terrain is mountainous). Essentially if you are forcing your opponent to react to you in the early/mid game you are not allowing them the opportunity to set up their mid/late game engine effectively. I can see that you may have issues late game as spider spam (sounds yummy...) isn't going to cut it, but I've really not explored late game options for Machaka since I've been too busy tweeking the opening phase.
However, Machaka has little problem going into death, and if you take an S5 or higher pretender it seems you will have some entry into Astral, other than lacking communion potential. In a big fight spreading 25+ spiders and having them attack rear means you are going to penetrate the enemy somewhere, and the quickened spiders are going to get to the rear and wreak at least some havoc though. Well in theory
You also will have access to all the nature and earth buffs.
As to dealing with an early SC... well again we can play at hypotheticals all we want, but if the end result is that you force your neighbor to go on the defensive then you have the advantage. An Indie5 setting allows for a single blessor and 8+ spiders (which is 1.5 turns of recruitment, and by turn 10 you can pump out two of these every 3 turns) to basically eat everything in their path, so you can easilly have a couple of these armies adding to your empire while your main host ties down the enemy, and their strat speed means that given anything other than completely unfavorable terrain, you can reinforce your front rather quickly.
What suffers is research, and it probably suffers greatly compared to research nations.