Since I'm unsure what you meant by your metagame description (
please be more specific!), I'll just post my *general* answers to your questions.
Quote (Elmdor @ Feb. 15 2003,22:47)First off about keeper and ose, I've seen the abyss played maindeck and moat sideboarded pretty frequently. I was wondering why moat wasn''t played maindeck or why there wasn't a second abyss played in the sideboard.
Mainly, the 2WW casting cost of Moat makes casting it consistently a bitch, especially against a wall of disruption, mana-denial, or counters. Plus, many decks are able to work around Moat, so it isn't a sure-thing against tough aggro match-ups when it does manage to resolve. If Moat had a casting cost of 3W, then the situation might be different. I like The Abyss better, since it's able to remove an opponent's creatures, rather than just letting them sit there as they try to topdeck an answer. Also, some creatures don't need to attack to do damage and/or help an opponent's board position (e.g., Triskelion, Goblin Welder, Gorilla Shaman, etc.).
In addition, it depends on your metagame whether or not maindecking a Moat is the way to go. It's a decision you'll have to make based on what you face most. But, whatever you do, don't put an extra The Abyss in your sideboard. It's just a waste of a slot, since 1x The Abyss is enough in the maindeck, and having another wouldn't improve any of your match-ups significantly at all.
Quote (Elmdor @ Feb. 15 2003,22:47)Also I had wondered if the discussion over impulse/brainstorm in keeper and ose decks just came down to a decision in personal preference or is there an actual verdict.
I don't think there's been any actual verdict, since there are strong proponents for both.
My opinion (if it means anything)? Brainstorm w/ shuffling effects > Impulse (when it comes to Keeper).
Quote (Elmdor @ Feb. 15 2003,22:47)Which card would be the best life gain substitute in a aggro/jank metagame orb/renewed faith/cop red (sb alter reality)?
The majority of the time, this is how I break down this decision...
Metagame w/ lots of Sligh & other burn-based aggro: MDed Circle of Protection: Red w/ SBed Alter Reality.
Completely random or unknown metagame: Zuran Orb.
Metagame w/ little-to-no burn: Renewed Faith.
Currently, I've been running Renewed Faith in an environment w/ a fair amount of Sligh, R/G Zoo, and Stacker 2, and I couldn't be happier w/ it thus far. It's never a dead draw, since it cycles, so I'm always pleased to see it, even if I don't need the additional life gain. You'll need to test out those three cards and analyze your own environment to figure out which is better MD slot choice.
Quote (Elmdor @ Feb. 15 2003,22:47)What would the recommended tutors be in a standard type ose or keeper? Specifically for my metagame?
If you don't end up including the Power Artifact/Grim Monolith combo (I don't use it, but some feel it's needed against aggro; to each, their own), then the usual tutors used are Demonic Tutor, Mystical Tutor, and Merchant Scroll (and 2x Cunning Wish as a sideboard-tutor). Some Keeper players still run Vampiric Tutor, so once again, you'll have to do some testing to see what you believe works best.
That's all for now - I'm exhausted today, and my brain is shot. If you want to take a look at my personal Keeper decklist, then just PM me, since I feel including it in my post wouldn't add anything to the discussion.
Good luck!
