I dont think the effeciveness of the powerdown will disapear with the introduction of Hive.Loans.
What you are missing about hive.loans is the liquidity. No way there will be say 50M HIVE liquidity on hive loans to be any real threat... even if 10M move around that will be noticeable.
Good point. I would counter that the illusion can be damaging on its own.
For instance, if there's 10 million in liquidity, which is definitely achievable, even the biggest stakeholders could start vote-selling and then try to get out before everyone else.
Every person with a million hive power could just sell his vote while things get gradually worse. At some point a few of those people will cash out instantly and maybe at this point others will be concerned about liquidity.
This could create a situation similar to a 'run on the bank' while keeping short term incentives alive because of stakeholder shortsightedness. People who sell votes are usually not the brightest anyway.
Obviously it's not that dramatic and we don't know how it will all play out, but better be safe than sorry.