Waiting your feedback about the link of my previous answer.
The article linked by you is well written. It covers a lot of problems and suggests solutions which are quite reasonable. However, one thing drew my attention.
[...]It will be very dangerous, if a counterparty has an older state, where all or most money on his side, because it becomes very lucrative to cheat (risk almost nothing for a chance to get all channels funds)[...]
User should keep untrusted counterparty from exhausting a channel
Solution: a minimum collateral should be set automatically (especially if routing is enabled), but user still should be aware of a problem and not change default settings when dealing with untrusted nodes.[...]
That's why
eltoo was proposed. It will be an alternative to the current penalty system.
A softfork is needed. Also, it's not possible to spend all funds that are locked up in the channel - there is such a thing as reserve which is a minimum balance that channel must maintain. For example, one of my channels has 0.0049 BTC capacity; the reserve is 0.000049 BTC.