Survival Map - Character Roles

Introduction
I'm making this survival/exploration map, pretty much the sequel to my Goblin Exploration Squad (loosely based on the idea of Ice Troll Tribes), where you use items to build stuff. And stuff like that. This one is, however, much more advanced.

I have 4 character classes set out, and on paper they seem to work fine, but in an actual game some people chill around doing nothing while others have to run around doing item drops and stuff - simply because of the hero they have.

Besides that, I need some suggestions for more abilities for the various classes.

The Story
You and your mates' Zeppelin crashed on an island with an area of not more than 100 m^2. Somehow, you have just enough of the necessary resources to build a crappy ship and get to the next island, to survive further! Do it.

Building System
A quick explanation:
In Ice Troll Tribes, you pick up the various items in order and gain a Ivory Tower-like item.
In this map, you place Blueprints (dummy building unit with an inventory), then drop all the necessary items in it, as well as the plans for it.
E.g. I want Camp Fire, so I build Blueprints (Small), place the Camp Fire plans in it, as well as 2 Lumber and 2 Rocks. Then I press B and it builds.

In my opinion very effective, but it takes people a long time to understand it.

Any advice?

Herbalism
Another epic feature in this map is the making of potions using herbs. Not quite as simple as the DotA recipe structure, this one requires different amounts (in terms of item charges remaining) and such.
Method: Build Cooking Cauldron, drop items in it, use it Stir It Up ability.

Seems to work well, but how should I improve this?

The Classes

Engineer
(Tinker)
Role: Building structures, ships, etc.
Abilities:
Construction (passive) - allows you to build better blueprints. (construction explained earlier on)
Drop All - drops all items on the target unit. Great for building things, perma-right click/left click because a massive hassle, as it did in Goblin Exploration.
[need further ideas]
Difficulty: Hard
To play this class, you have to know what you're doing. Very weak in terms of combat, and slow. Only class that can build!

Shaman
(Tauren Spirit Walker)
Role: Making potions, healing, reviving allies
Abilities:
Cauldronology - Allows the placing of cauldrons and eventually revival shrines.
Harvest - Turns the terrain beneath your feet into an item. Essentialy for finding the right ingredients for potions.
Replant - The opposite of Harvest, can also be used to make rocks and other materials into terrain.
Difficulty: Medium
This class is designed for those who like to explore different item combinations and stuff, I should probably rename it to The Horadric Cubeman. Also very week, but essential for healing and stuff.

Hunter
(Troll Berserker)
Role: Hunting, carrying corpses for food, killing bosses
Abilities:
Carry Corpse - he can carry corpses!
[seriously need more ideas here]
Difficulty: Easy
All you need to do is run around and pick up items, kill stuff, and pick up the corpses. The only character that is not needed, but very good and self-sufficient, especially early game.

Berserker
(Grom Hellscream)
Role: Tanking, deforestation, fighting overwhelming masses
Abilities:
Blade Whirl - Like Bladestorm from ladder or Counter Helix from DotA, except different. Spins for .25 seconds more per enemy in range, and taunts them.
Combat Mastery - evasion and critical strike
[more ideas please]
Difficulty: Easy
Essential to get lumber, dangerous when spinning near allies. Meant for noobs.

Dependancy
The Engineer needs the Berserker to get lumber.
The Hunter needs the Engineer to build a Camp Fire.
Everyone needs to sleep in a hut built by the Engineer every now and then to keep their stats up.
Basically, this game can't be played alone.

Final Words and Requests
Besides the much-needed ideas for abilities, a few more questions:
What should I name this map?
Should the characters maybe be renamed to Goblin, Tauren, Orc, Troll? Or something else?
Should there be automatic revival early game?
Is it okay to have 2 classes geared more towards noobs?
Should the starting area rather be on the mainland, with more resources?
Should all classes have some level of building, carrying corpses and all that?

Thank you for your time.

did you ever finish this project?

you probably should have asked him privately