Building a tabletop RPG from scratch

You might also look at Return of the Heroes. You can find many things on BoardGameGeek using advanced search.

I beg to differ, sure I can see how a game with D&D weight or heavier might be hard and time consuming to design, but i would like to argue hat board games are not the medium for complex stat trees with minor modifying effects.

Fiasco is a pretty popular RPG game without a lot of stats, and if you are looking for an RPG that takes an hour or less to play there are plenty of options out there (altough i guess technically they are more story telling games then RPG's). after reconsidering your initial post i realised that a story telling game does perhaps not work out with your #2

have you checked out http://sidekickquests.com/

its for kids, but if you are planning on introducing an adult, i think they can handle Savage Worlds or D&D just fine.

Look at the FATE CORE system which is simple and can be quite family friendly. It doesn't require a lot of heavy number crunching yet it can hold some depth where it needs to.

This is definitely something I have spent quite a deal of time thinking about: creating a mass market game for an rpg genre, D&D meets Settlers, so to speak. Here's my thoughts on your list:

1. Simplicity - This is always the biggest barrier. At least for me. RPGs are by nature very complex, and in some respect, that's the appeal of them (the ability to have huge variances in gameplay while using the same rules, customizing your character, becoming attached to your personal settings, scenarios, etc). You've got some good suggestions from others as far as other RPGs to look at that have tackled the simplicity issue. I would look at the simplest, and also check out very simple board games, card games, etc. See what makes them easy to understand, while keeping their fun factor. One thing I've noticed is just that math is unpleasant when doing a game. Or at least, remembering equations and numbers. I would make sure every stat is a simple number that you can simple add and subtract with. (One attack stat, one defense stat, etc, instead of calculating if you hit first, then again for damage). Not the best explanation of my thought process, but I hope you get the picture.

2. Strategy is something that has to be balanced, and really depends on how you structure your game It may be easier to give the appearance of strategy for a family game, than some complex strategy.

3. I know it's a very simple example, but this is one of the reasons Monopoly has been successful for so long, even without a lot of variability and strategy: It keeps you engaged during other players' turns (You are always watching to see if someone is going to land on YOUR property!). Don't skip peoples' turns, and don't allow them to get a glass of water while everyone else is playing. Try to keep everyone involved during everyone else's turn.

4. I wouldn't worry about this one yet. Make a great game first. Expansions will come after. But I think the obvious option, just so you know it's possible in the future, is what I'd call "worldbuilding". Creating settings, adventures, scenarios, premade characters, etc. for less imaginative players. Some like to create their own stuff for your RPG system. Others will love knowing that that stuff already exists. Again, focus on making the game, the mechanics etc. NOT the expansions.

5. This is another I wouldn't worry about too much. Especially right now, but even in the future, if you're sticking with the RPG focus. Manufacturing solely printed materials (ie, rules books, cards, character sheets, etc) which is all that you need for RPGs, is dirt cheap compared to creating bits, board, box for a board game. There are plenty of Print On Demand publishers who will sell you only copies that you've sold, and will charge you next to nothing for copies you get yourself. Finally, if you will be manufacturing to sell, and desperately want miniatures, pieces, other stuff that would be expensive, figure out your cost and financial needs, how much you want to make from your project, etc, then kickstart it, so that you know you have enough traction to publish without digging yourself a hole by ordering product no ne will buy from you.

Hope this has been helpful. again, this specific question is very appealing to me, and something I've done loads and loads of market research and logistical planning for, so if you want any more information or thoughts, let me know!