Some very good questions are raised here.

Difficulty and gameplay. Are they different animals, or merely two sides to the same thing?

Is harder better? more realistic? Not in itself, but if making a sim more realistic makes it harder, then I'm of the persuasion that harder
is better.

One thing that makes any flight sim harder than real life, is the lack of any physical sensation, in terms of "seat-of-pants" feeling.

Difficulty is very relative in terms of the user, a complete newbie at flight sims will find any flight sim more difficult than a seasoned
flight simmer.

Flying a sim a/c in a straight line and doing basic manouvers after a bit of practive is probably whithin most peoples reach. But getting
the most out of the a/c and flying it with excellence, is probably a lot harder.

Motivation is also very different. There are propellor heads that need the sim to be a credible experience in tems of difficulty and the amount of time it takes to master the a/c. People who are willing to spend quite a lot of time to study the differenet a/c and how to fly
them properly and who care about the sim a/c being as close to real life perfomance as is possible. Who like to get the feeling that "if I
were a better pilot, the sim would actually be able to let me execute this or that manouvre to as near perfection as I could get it".

Then there are people who seek another experience, who primarily want to fight the AI or the multiplayer, or to a lesser degree think
about historical or engineering accuracy.

And people who range anywhere between the two.

All points of view are valid and one pov is just as good as the other.

Some want the full monty, others can do without, I think it's important that the choice is there for the individual user to make. No one else.

That is why I believe that any sim should have scaleablility in terms of tuning the realism level for flight model, AI, campaign goals etc.

And what do we mean when we use the term of "balance"?

Does it mean that the a/c in the sim should perform in such a way that the a/c that in real life was the better a/c, will also be the better
a/c in the sim?

This is one good use of the term.

I would also suggest that the balance between the physics engine and the data going into that engine should be balanced. I've tried other's mods, and made some of my own minor mods, for sims or games or whatever I should call them, where I found that the modded data going into the engine were more correct than the data that came with the sim, but the endresult did not quite live up to my expectations.

My main thought about those examples is that the physcis engine and other important parts of the sim; i.e. the coding of the controller, in those cases really were not designed to use real life data, so the whole experience became unbalanced.

IOW: it seems to be possible to have a very good physics engine and implement data that makes the sim easier, but it doesn't seem as feasible to to go the other way and put in better data if the physics engine is not really up to the task.

Then there is also the balance in terms of the package. The perfect package in terms of balance for me would be:

- One huge map where I can fly anywhere, as I always felt that being given just a small part of the front in a map, to be very confining
and detrimenatal to my immersion.

- Replays and saveable, editable replays, OK, it's not just to admire eye-candy, but more to study the areal manouvers.

- Optional Flight Training; I'd love to enter flight school in say 1915, be given a bit of instruction, dual flight, gunnery, solo and "you're off son, they need replacements in France..... now"

- Quick Shots like in Rowan's BoB; great for the times when I have little time but would like a fairly concentrated battle.

- Campaign, and again I think Rowan, or RB3D are the benchmarks to aim for.

- Ground details; for a WW1 sim the trenches, troops moving to and from the front, flying over the troops as they go over the top. The environment which has been mentioned more than once.

- Multiplayer

- Good, intuitive and simple menus

- And easy to use tweaks to the controller settings, because bad controller settings can completely ruin the experience, and the developers are not always giving us the best settings.