You have done the first best thing which is reaching out to a community of players which will potentially buy such a game. In doing so though you have to manage expectations so my first suggestion is to publically maintain a crystal clear feature list of what is in and what is out, or a "to be determined". This should help you avoid grief and time.
If you are aiming for a tablet release first with iOS it would seem obvious to me that Android is covered too. Personally I own an Android 4.3 tablet I do not own any iOS device and have no plans to in the future. Android market share is growing and I believe is above Apple now in tablet sales so I'm just saying that you will cut off a chunk of potential users with an iOS only approach.
One trend in Sims atm that seems to be working well is the combination of realism, detail and tutorials teaching the player about the object of the simulation in great detail. The study sim in effect, it works well for the DCS series and they are undeniably successful.
If you are going for a tablet release why not incorporate some unique selling points of the platform such as the gyro sensors. Turning a periscope and using a tablet like a view finder could work really well imho.
...and good luck, you've got my interest.
