MArcomage

Basic gain 25, additional gain 10, effect:
Additional production based on played card cost category (Bricks only - Bricks x3, Gems only - Gems x3, Recruits only - Recruits x3, Mixed cost - overall x2, Zero cost - x0).

Cards that should have this keyword:
Elven apprentice
Dwarven miners
Librarian
Wizard
Priest
Merchant

Apprentice
Architect
Blacksmith
Book of magic
Foundry
Legendary smith
Master bricklayer
Mentor
Merchant ship
University

Ancient sage
Governour

The idea is to return dedicated prodiction/facilities+ decks in game since Alliance is dead without dwarves (especially Chaos dwarf). Gameplay-wise facilities+ cards have some good synergy with production cards but pure resource cards (especially Restoration) are better. When you play, say, Book of Magic at round 10, you receive +1 magic for 12 gems, so you will restore your gems level only to round 16 (if you play something with bonus production - it will be faster, but not with gems since most of production gards cost gems).
Now what you will have if you play Meditation at round 10? It costs 15 gems, but that doesn't matter anything because it's self-paying card. When you play it, you will immediately restore gems loss and receive additional 10(+) gems - that's 3 turns with standard production and 1 gem over it. And it's just Meditation by itself, not after Mage or another Restoration.
See the difference? With resource card you will receive gems level of round 16 at level 10 and vice versa with magic+ card. Of course, it's an extreme example but there is the same thing with another facilities+ cards. You play cards to raise resource income, while enemy just builds his tower or destroys yours.
Production/facilities+ decks have very little chance to play successfully, and I think that it should be fixed with something like this.
What do you think?

All that you say is true but i don't really think that this change will solve anything.
The trouble is that production/facilities+ decks have lost its importance due to a creation of a large number of stock gaining cards which are better suited to certain decks then production/facilities+ cards.Even with your proposed changes i cant see those cads replacing for example crypt and crypt serenity in undead decks, restoration in mage and legend decks, holly stock+ cards in holly deck, no key stok+ cards in no keyword decks.... because they simply have a better synergy with this decks. Alliance where a great support cards but unfortunately they too where pusht out by the new cards.
Alliance has a great synergy with production/facilities+ decks unfortunately like you have already sed alliance is pretty much dead on its own. While it can generate a large number of resources (especially in the long run) it has pretty weak attack and no real defense.Despite of that i think that alliance is the best chance of bringing facility+ cards back to life although it will require a couple of good new attack and defense alliance cards to bring that keyword back to life.

Well, Mage/Legend decks have a big benefits from facilities, because there are many Mage and Legend cards with Swift.
But I don't want to force Undead or Holy leave treir stock+ cards, I want a new deck core which should have a synergy with Aliiance, Mage, Unliving and maybe Soldier. A core based on facilities+ cards, that can make that facilities work faster. Not when your tower is in range of Last hope or enemy's one will be fully built with Gentle touch award.

I know what you want and mean believe me i would like the same thing ! But like i sed the thing is i don't see it happening with just this change. Dont get me wrong i would wherry much like a working facilities+ deck but i cannot see it having the desired affect unless a lot of other changes are implemented first. Like strengthening the alliance, reducing the gain of crypt and crypt serenity.