Hearthpwn

Mulchmuncher: 3 stars
This card needs some support, but with only Soul of the Forest and Living Mana the cost starts to decrease a lot. It's very reminiscent of Corridor Creeper.

Tending Tauren: 1 star
Mini-Cenarius doesn't seem very playable to me. High cost, choose one between win more or slow stats. Seems meh to me. I'd say it's mostly bad compared to Fungalmancer, but it is more flexible. I think the cost is what ruins this card.

Landscaping: 3 stars
Good stats for its cost and synergizes with Mulchmuncher and other token druid cards. I don't think it deserves a 2 in your rating system.

Goblin Prank: 1 star
The card itself doesn't seem that bad in a vacuum. There are several scenarios I could think of where it's decent. But... I don't think it will realistically work and I don't think it's worth cutting cards for this.

Fireworks Tech: 2 stars
If a hunter mech deck would work, this would be an easy fit imo. Considering how you rated other mechs, I think this should at least be 2 stars.

Secret Plan: 3 stars
This has a lot of utility, because it basically allows you to play a third copy of any good secret in a spellstone or spell deck. This also allows you to choose a secret based on your current matchup. I think it's great!

Stargazer Luna: 4 stars
This card seems really solid to me. I might be overhyping it, but I think it has more applications than in tempo mage.

Astromancer: 1 star
Whereas you don't believe in hand mage, I seem to really not believe in hand mage.

Meteorologist: 1 star
^

Kangor's Endless Army: 2 stars
You gave it a very optimistic rating considering the rating you gave to other mech cards. I'm not even sure I would play this in a mech deck if I could. But there is a slight possibility, which is why I give it 2 stars (would need to make sure it doesn't get too many low-cost mechs without buffs).

Crystalsmith Kangor: 1 star
I want to believe in this card, but I don't really see heal paladin working out since there are so many combo decks out there. Also it probably isn't good enough in control paladin if that deck is good.

Annoy-o-Module: 2 stars
I'm not sure mech paladin is that great, but I think this card would be pretty good in that deck. This might be an optimistic rating though.

Crystology: 4 stars
This is obviously a fantastic card, the only counterargument would be that the decks this card fits into could be bad. I believe this can find a home in at least one good deck.

Autodefense Matrix: 1 star
Meh. I might play it just for fun in a Prince Liam deck or something and it could be a good option from Hydrologist, but otherwise I don't see this working out.

Glow-Tron: 4 stars
This is an auto-include in mech paladin, but further than that I think it could also see play in a non-mech deck!

Zerek's Cloning Gallery: 2 stars
The potential I see in this card is probably in a quest priest deck, or a very high-rolly option in a big priest deck. Considering it's high cost and unreliability (you could draw your minions before you play this card) I don't see it as a good option in a combo deck. I think 3 stars is too high in your rating system, anyway.

Zerek, Master Cloner: 3 stars
Ok, this might seem crazy and it's probably one of the ratings I believe in least, but: I saw this being played at the prerelease and holy moly. It seems much stronger than I initially thought. However, it is important to note that the prerelease only had basic and boomsday cards, which probably makes it much better in that meta. But I think this might be a sleeper card. Really good combo in quest priest with Reckless Experimenter and Vivid Nightmare.

Reckless Experimenter: 3 stars
I think this needs more support than you say, but I still see its potential.

Extra Arms: 1 star
I'm really not seeing this card working. It's only actually good in conjunction with Radiant Elemental, otherwise the cost is too high. If there's some kind of zoo priest with Radiant Elemental as a focal point, maybe, but that probably won't happen.

Test Subject: 2 stars
I'm rating this 2 stars because of the combo (look it up), but. Eh, not entirely convinced by the combo.

Topsy Turvy: 3 stars
Not only would this see play in the combo deck with Test Subject if it actually works, but it seems like a really good option in an Inner Fire combo deck. I don't see how it's a tech card.

Necrium Vial: 1 star
Meh, what deck would you put this in? It seems fun but not that good.

Blightnozzle Crawler: 1 star
Meh, again. Vilespine Slayer is in most situations better.

Crazed Chemist: 1 star
Arena card. Not really seeing it work in constructed.

Violet Haze: 2 stars
It has a lot of variance, but the reason for my rating is that it possibly gives more fuel to Tess Greymane. But wait that's a meme deck. 
Violet Haze: 2 stars 1 star

Thunderhead: 3 stars
This might also be one of the cards I rate too high, but man. I actually believe that some kind of token shaman deck could work, and this would be great in it.

Storm Chaser: 4 stars
Just a really solid card that will easily fit into many decks. Often a 1-off probably, since there aren't that many 5- or more cost spells in shaman, but still a really good card.

Voltaic Burst: 3 stars
Rating this high for the same reason as Thunderhead, I believe in token shaman (might still be hilariously wrong though).

Menacing Nimbus: 3 stars
This also seems like a solid card to me and could probably see play in many different decks (even shaman, elemental shaman, token shaman?)

The Soularium: 4 stars
This goes into every single zoo deck, right? So why 3 stars?

Nethersoul Buster: 1 star
Hm... it reminds me a bit of Darkshire Councilman, so it could be dangerous to rate this 1 star. Actually, would this be good in heal zoo? Crystallizer could also work in heal zoo. There definitely is potential... but I'm just gonna go ahead and rate this 1 star anyway.

Soul Infusion: 2 stars
This is better than something like Smuggler's Crate because 1. It works on all minions, and 2. You basically get to choose the target. Together with Doubling Imp and Saronite Chain gang, this has incredible potential. But, alas, it might be too slow for a zoo deck, and I'm unsure if 2 stars is a good rating for this card.

Omega Assembly: 3 stars
This gives you a lot of value in the late game (well, it could also give you 3 1-drops but how likely is that anyway). It would probably be played very rarely before turn 10 but having the option is a bonus. However, that also makes it a dead card for the most of the game. But I still think it has really nice synergy with Dr. Boom, Mad Genius and is just straight up a nice value card in control warrior.

Weapons Project: 4 stars
Great anti-aggro card, breaks weapons, amazing synergy with Harrison Jones. Do I need to say more?