Anyone who thinks defaltion is a good idea is essentially thinking that their small cash pile will magically grow to be worth more without them doing anything, which seems enormously attractive because it's a) easy and b) there isn't any of that unpleasant risk that comes with investment, and which makes it so hard to decide what to invest in. So everyone who has money stuffs it under the metaphorical mattress, and people who don't have any can't get any because the supply of credit has vanished. Economic growth slows way down.
Under deflation the same computer would cost half as much 2 years later, and you would only have half as much income to spend on it.
Under deflation, though, everyone has less money so I have to keep cutting my rate to stay competitive. Now even though I'm more productive I'm getting a lower return on my productivity. Arguably,this is a problem currently facing much of the labor force in the US.
Any economic situation can be good for individuals who are positioned to take advantage of it, but in macro you need to consider the economy as a whole, through to food and extractive industries etc.
The Great Depression was pretty bad for people trying to get by in life, no?
Regular people invest when investing makes sense, when the creation of a thing like a restaurant or a farm or what have you has significant value in and of itself. NOT because they value money, and the value of their money will decrease if they don't invest
Having the power to control inflation to force people to invest is tantamount to setting their mattresses on fire to get them out of bed in the morning so they'll go to work. People will get out of bed--and invest--when it's right for them, and they don't need people like you to goad them into it.