Hello,
Let me explain myself before you read on.
This concept is similar in workings that have already been made...
Okay The minecraft steampunk community has been satisfied with very well made texture packs such as Glimmar's and mods such as the airship, plane, and zeppelin and other enhancers like the aether/tekkit/BTW etc.

These are all nice but none fully capture the "feel" of it the texture pack gives aesthetic appeal but fails to satisfy the engineering aspect. the plane mod gives parts and the creation but limits the creativity of the pilot same with the airship mod...but the airship mod does run on steam and requires maintenance... this is by far the closest out there to how the feel should be...the zeppelin mod is great for creativity but it is very static and doesn't give the feel of control and actual flight, but more of a remote control toy...the aether is a magical add on that gives you a wonderful up high dimension full of steam style floating islands and serene scenery and fantastical features... tekkit has a sophisticated engineering system but it is very linear in the sense that it is powering and the moving with energy stored and efficiency...all of these are fundamental but they don't scream steam even the "Steam Engine" fails to match it... I am not saying these are poor alternatives, but they are not actually steam powered (With the exception of the airship).

So on to my concept. These are good reference for a comparison that's why i put the previous notions forward...

Concepts

1. Engineering Parts
   
2. Designing a Vessel
   
3. Different Types of "Lift"
   
4. Piping Design
   
5. Maintenance & Repair
   
6. System Monitoring & Control
   
7. "Life-like" Systems
   
8. Upgrades
   
9. The Feel of the Wheel
   
10. Freedom of creativity
    

How and Details

1. Engineering parts- Highly Similar to the plane mod or the airship mod in the sense that you use various materials to create individual parts of the vessel but unlike them these parts are placed not assembled in a crafting recipe...but more on that later.">..
   
2. Designing a vessel- Since mods have limits there is of course more limits on how personal your vessel can be...but like a mod not mentioned before called build your own ships you start with a basic frame and can add a mast a keel and other such ship parts, but a concept that is like a combination of the copy/paste feature of tekkit mixed with the block recognition of Zeppelin...To explain more clearly you would build a part and then assign it as an actual part of a ship it would be an entity like in the zeppelin, but would act as a blue print from tekkit and could be attached as a part of your ship...like the components in the build your own ship mod.">
   
3. Different types of "Lift"- two in mind are a hot air and propellers, but there would also have to be stabilizers like wings and fins and such... these would probably be assigned like the rest of the parts">">
   
4. Piping Design- The Engineering parts such as engines, boiler, pressure release, propeller, and gauges would be connected through a piping system highly similar to tekkit piping because they would pipe liquid and steam to where they need to be and the parts would interact with them preforming a function necessary for a steam powered system to work
   
5. maintenance and repair- This section is more of an adding realistic problems like the pressure gets to high a pipe bursts over heated engine explodes/ catches fire...water levels/fuel levels too low to produce sufficient power causing loss in altitude. maintaining haul integrity and fixing things after a crash...pretty much all of the things an aviator would have to look out for. I have an idea that plays out like this the machines would work similar to the damaging of anvils but alot more durable
   
6. system monitoring and control- this makes the previous matter easier by monitoring all of these things such as steam pressure, water levels, engine heat, etc
   
7. life like systems- meaning they will wear out over time...probably through the minecraft durability system, but tools such as wrenches, spare parts, and scrap metal could be used to prolong the lifes of these. Note: these wear outs will be very very slow and will be an occasional inconvenience.
   
8. upgrades- parts like high quality pipe, and higher powered engines... better boilers...etc all of the things to make your ship shine">
   
9. The Feel of the Wheel- A feature that makes the pilot feel in power instead of remote control a steering wheel will be the way to control the ship. it will be like entering a minecart and you will enter a view where you see the wheel and it will turn the way you do giving you the feel you are steering the wheel.
   
10. Freedom of creativity- the mod will only require the parts not for them to be specifically placed though the parts must be linked correctly...the creativity doesn't stop with the basics you can arm your ship...give it a cargo hold...design a personal banner to raise...and it must be multiplayer compatible because whats a captain without a crew...a captain with a lot of work on his hands.
    

How it Improves the game

Even being a tedious and expensive this would still be a great improvement to the game. For one it gives direction for furthering your gaming experience...meaning you have to really work for it for it to pay off, but I imagine the payoff will be worth it.

The benefits are it first of all gives people in survival mode the ability of flight and mobility, but it would also be the most efficient travel. Boat travel is the the most efficient travel in the game...but their isn't water everywhere... Rails are the fastest travel but they are expensive, take up space, and must have a track set for them to follow...An airship would be able to travel freely in three dimensions and much more efficiently then boats because they are engine powered...but they are also more weighted and are effected by gravity ...the more engines you have and more propulsion systems the better the speed and mobility...it is similar in concept to redstone mechanisms in the sense of the more complicated/layered/thought out systems produce better results.

One of my favorite parts of the concept is that the ship and its parts are all full customization you can have any size or look that you want which gives a great open building process the only parts i think that wouldn't be customizable would be propellers and the machines, though everything that doesn't have free customization would have various alternative looks and types.

Overall it would probably evolve into something more but this is a great start I think and would make an amazing addition to the minecraft experience

So I hope you guys like this Idea...maybe this may revolutionize the entire community and a passionate modder will start this...i just want you to know I....I am not that modder...i would gladly look over it and give insight, but i have neither the know how or the time to take on such an amazing feat
Comment/Give Feedback/Other stuff you guys do...If you think of anything that would improve on this please post it below :]