It seems Bitcoin price drop caused lower personal valuation of bitcointalk accounts by some owners and looks like lenders realized this phenomenon a bit later.

Few recent lending examples to explain you what I mean:

grtthegreat :
- hero member preferred to lose his account for just 0.04BTC ($150): https://bitcointalk.org/index.php?topic=5102198.msg49422126#msg49422126
- legendary member dropped account just for 0.05BTC ($200): https://bitcointalk.org/index.php?topic=5087785.msg48904269#msg48904269

my case:
- legendary member who already repaid 2 loans before BTC price drop has defaulted 0.04BTC non-collateral loan and is not carrying about negative trust: https://bitcointalk.org/index.php?topic=5101704.0  

shasan:
- hero member defaulted 0.03BTC ($100) non-collateral loan and ruined his trust: https://bitcointalk.org/index.php?topic=5030169.msg48734465#msg48734465


At the same time let's see few accounts offers examples:

- Legendary account for 0.015 BTC
No negative feedback - Never requested loans - Never banned.
Position - Legendary
Posts - 1119
Activity - 1119
Merit - 1018
Trust - Green trust
https://bitcointalk.org/index.php?topic=5091528.0

- Legendary account for $150
https://bitcointalk.org/index.php?topic=5094226.0

- Hero account for 0.01BTC
https://bitcointalk.org/index.php?topic=5096756.0

- Full member accounts from $50 to $130
https://www.playerup.com/accounts/bitcointalkaccount/?order=price


So as a conclusion, I propose to consider current accounts valuation drop while accepting non-collateral or account pledged loans.
Therefore loanable amounts for such loans should be lower than acceptable "exit price" for hero/legendary members. My current estimate is: up to $50 for legendary and $30 for hero members. Another question are such loans make sense for both parties
 
P.S. Im not going to blame all legendary/ hero member because of few black sheeps and won't break existing trust based relationships on lending section