if it's a voluntary agreement
An agreement that most people don't want to sign up for.
The purpose of the power down period is not just to keep people from cashing out.
Good because it doesn't.
It's also (perhaps moreso) to encourage voters to vote in ways that promote the platform's long term interests instead of focusing exclusively on their own short term interests. Vote for the article that will attract users and raise the price of steem, instead of the article that will attract whale votes
You assume that if we remove steem power people won't be invested long term anymore, this is where my analogy doesn't fail :-)
So that's even less of a reason to worry about friction.
I don't think that's what liberosist meant by friction. There is friction because the barrier to entry is high due to lock in period. The majority of users don't want to lock their money which means many users are excluded from participating.
Steem power also adds a lot of wallet complexity which is bad for mainstream adoption.
Authors don't need steem power to participate. Long and short term traders don't need steem power to participate.
If someone wants the privilege of voting to shape the nature of the content on the blockchain and the distribution of rewards, then I think it's fair and prudent for the content community to demand a demonstration of long term commitment to the platform. It's sort of like "proof of stake" at the content layer.
Possible compromises: Early withdrawal with penalty, distribute rewards as steem instead of steem power.
I know what you mean but i think the benefits of eliminating steem power outweight the benefits of keeping it.
It's also going to be more and more difficult to own a large piece of the pie as more users use steem and as the price increases, so the problem you mentionned is going to dissipate with time.