While you're playing beta 6, I'm brainstorming stuff for the next release, including:
- ASCII mode improvements
- changing prices so that the game operates on a silver standard instead of gold standard
- introducing a parry bonus such as in Incursion
- body parts system and the effects of hitting them
- adding weight to money and banks you could deposit it in
- using a defense roll instead of static AC
Some of the changes proposed are a pretty radical change compared to the game's d20 roots, so I would like some opinions.
I don't think there's any harm from deviating, but there is some merit in being a roguelike that sticks to d20 rules. I don't know any others that do.
As far as your suggestions go, I completely agree with getter77 that economy is difficult. I personally like collecting gold rather than bartering, but it needs to be carefully managed. I think the best way to do this is to go down the Baldurs Gate route where most things don't sell for much, but cost a lot to buy. Only things that are of actual consequence are worth selling, and that's because there's an actual trade off.
Adding weight to money is normally annoying I find, especially as it tends to be the one thing that you can drop in increments. Lets say your burden weight is 25.5, and you're at 24.0 and want to pick up a 1.6 weight sword, you then have to go in and drop enough gold to pick that up (and so on).
Body part systems are good, but that leaves you open to a lot of things that can quickly become annoying (head criticals, wandering around with a broken arm you can't fix) unless you balance them really well. I think it's a great way to go, but I'd urge caution as it's a huge undertaking.
Parrying sounds good though, although I personally prefer static AC.