Your points about spellbreaker were noted, and I also feel you may be correct in the case of this deck, but the owl in my opinion is a better choice for a lot of decks as he lets you silence, and still make a move that turn. Spellbreaker, while a bigger minion, IS your move a lot of the time because of his cost. But Spellbreaker has been good to me in here.
My thoughts on earthen ring farseer and voodoo doctor are that, and I have found, the deck can lose pretty bad to really fast hunter and rogue aggro, and I need some way to not only force a trade with my opponent, but at WORST, force a removal card, and slow down their tempo via the health gain. I am not often using life tap against these all in aggro decks, so it does help slow them down. More testing is necessary but It appears to help, moreso than other minion options presently.
I still am not convinced on the Gadgetzan as there aren't that many low casting cost spells, and I'm not about to run Sense demons and Gadgetzan combo so that I can get +1 card (-1 2 cards gadgetzan & sense for +2 demons +1 draw).
That said, I have tested a lot of different ideas lately, and finally settled on a successful build that has been working in Masters 3. Far better consistancy than the other warlock decks I've played thus far, or atleast resonates with my play style the most:
2 Twisting Nether
2 Shadow bolt
1 drain life
2 siphon soul
2 Voodoo Doctor
1 Acidic Swamp Ooze
1 Wild Pyromancer
2 Earthan Ring Farseer
1 Defender of Argus
2 Senjin Shieldmasta
2 Molten Giant
1 Ragnaros - This can be alextrasza or whatever you want, really (alex is prob better here, but I don't have one. Tried baron geddon, sylvanas, illidan - Ragnaros wins me the most games seemingly)
-- edited to rephrase a sentence --