Hearthpwn

Feral Gibberer may end up more powerful than we think.  We don't know yet if buffs copy to your hand.  If you can get one to stick, use Spikeridge on it and go face, and the buff copies... !!!

Unlikely?  Of course!  Being a 1/1 it may very well die as soon as it hits the board.  But even if you play it and cast Spikeridge right away on your turn 7 (6 w/coin) and it takes a little damage, say you get a 1 mana 3/4 taunt with the Spikeridge deathrattle in your hand.  I would call that major value!

I haven't, but it'd be similar to the Meat Wagon Warlock deck that Toast was playing on a stream of his a while back.  It would probably be worth it in those events where your opponent's last action is to kill the Meat Wagon and then you get basically get a free 7/7 with Charge.  If he kills the wagon and draws out the Doomsayer, he may be able to kill it right away.  However, in those instances the doomsayer is basically stalls for 7 damage, which may protect other minions on your board from dying.

The only bad thing about running Validated is that if you draw it, the card is a bit clunky on its own as it's 5 mana for a minion that can be cleared without any real consequences to the hero/minion attacking it before your next turn.

If you (player 1) play Marin and your opponent (player 2) has Umbra, I don't think it should trigger.  Look at the wording by replacing "you" on Umbra's test with "player 2"

Umbra's text: Whenever (player 2) summon a minion, trigger its Deathrattle effect"

When player 1 plays Marin, the chest is summoned on player 2's side of the board, but is still summoned by player 1.  Therefore, since the chest is not summoned by player 2 (the player who controls Umbra) it shouldn't trigger despite Umbra being on that side of the board.

Honestly, there are two ooze cards that remove weapons, another that removes a durability (will rotate out in April) and Bloodsail Corsair that removes a durability too.  If the weapons become a big deal, including the four ooze cards may very well be enough.  Harrison Jones could be good to add if you have him already, but until we see more about these weapons I don't know if anyone can say he's auto-include.

What about something simpler like each week Dungeon run keeps track of your farthest dungeon run, then at the end of each week you get a dungeon reward of 10g per boss completed on your farthest run of the week.

Best run of the week is beating 7 bosses?  Get 70 gold!  Best is 4 bosses?  40g.  Maybe for a full clear of 8 bosses they can bump it to 100g.  So basically giving the same reward as weekly Tavern Brawl, but you get to choose what pack you get as you're rewarded the 100g instead of a pack.

It's a small enough reward system of for easy gold in a single week that Blizzard could probably afford to implement it, and it simultaneously quiets some of the "Hearthstone is too expensive" chatter online as well as giving any new players an extra source of weekly income to start building up their sets.

Could be cards in the set for Warlock (perhaps the Warlock legendary weapon) that have spell cost reduction effects.  Which would make obtaining and playing Atari a more obtainable goal.

Don't forget Bloodsail Corsair being put in every deck... so nothing different there.

Don't forget that Harrison Jones and the original Ooze cards should always be available in Standard.  If any of these weapons start seeing significant play (should at least in the first couple weeks to try them out) then you can expect to see those cards in just about every deck to counter.

My guess is maybe there is another minion you can play that helps speed up the process of playing the seals?  Or maybe the Legendary Weapon for Warlock has a "Reduce all Spells by (#) Mana" so that you can pull this off quicker than you think.