* For trading, I agree with the annoyance of not being able to switch. But gold is never an issue, just press the 'add gold to balance this out' button that's right on top. Giving less gold never worked anyway, and only seems to ruin someone's attitude towards you, NOT a good thing.
* Barrels - Yeah, ice seems 'what?'... but poison barrels have been in RPG's for eternity, and make sense.