You asked for a constructive reply to this, so I'll try to give one.
We all agree that Ricardinho was one of the few positive additions made by Pep last summer. But KR made sure not to trigger his appearances related extension clause towards the end of last season, though still offered him a new contract.
It appears from these indicators that Pep offered quite a high wage, more than could be justified for a 33 year old left back from the Azerbaijani league. Likely the same situation for Pekalski, Mehmeti, and Tiendalli, too.
Yes, he was Player's Player, we all would love to have kept him around, he was impossible not to enjoy in yellow (and as a Brazilian, I assume he enjoyed being in that kit too). But we can't just keep people on at unjustifiable wages, no matter how popular they may be with the fans and squad (even though part of me thinks there is some of that behind Scott Shearer's extension).
And yes, we have already filled that void with a loan. An ex-England U21 player from Everton who turned down Championship clubs to come here. Did you have anyone specific in mind who you'd have preferred?