Here's a quick chalkboard analysis (Thanks to TotalFootballI iPhone app) of the Twente match. It might explain some of what we saw.
1.) Strong opponent
There are reasons for Twente only loosing one game this season so far, compared to Werder's eight lost games. Their counter attacks were brillinatly executed, as we have all seen unfortunately. The difference between the first - and second leg game when it comes to player influence is pretty revealing in that respect. Compare.
Twente first leg
Here the back four dominated the game.
Twente second leg
This time Ruiz with his quick vertical was in charge.
2.) Conversion. Compare how Twente got more close-range shots on goal than Werder.
Note how many dangerous situations Mielitz had to face! He is really a mighty good goalie! Not only saving balls but also our asses ;)
Werder did not get enough dangerous shots on target in the box (aside from Almeida's misssed header/rebounce Piz shot)
3.) Frings tacklings. Midfield deserted.
Frings as full back was, as to be expected, completely overstrained by quick-footed Ruiz and Chadli, as you can tell from his unsuccesful tacklings in the highly sensitive box area. So him filling in led to a midfield helping out the back four -- allowing too much space in midfield for a successful game build-up - subsequently, it was easy for Twente's players to disrupt our game already in our own half. Also Wesely would have been needed as offensive midfielder.
What would have been the better option you ask? Jensen as FB? No, for he was actually needed to initate the game (sth Frings is also not so particualrly good at) without him in the defensive midfield, we would have had even less promising attacks.
So maybe Silvestre, afterall? As it looks, he got spared, because of Werder "fans" whistling and booing him during the Nuremberg match. Their unfairness might have contributed to our particular situation as well then. I do think it's fair to bemoan that kind of behaviour, as KATS rightly did, but it is also fair to bemoan the fact this transfer did not work out as planned. Not by booing though. Which is no big deal, considering the many many successful transfers we have seen. Considering also the uniqueness of the situation, when not only Boenisch, but suddenly also half of the entire starter formation was injured. Unfortunately, shit hit the fan. Boenisch called in sick longer than expected. Also Pasanen is frequently ijured. Naldo could be compensated by Prödl.
Still, no matter how rubbish a player performs, whistling is not going to boost confidence. I don't think he perfroms intentionally bad. Under the given premises that all fans should be aware of, as I have tried to outline above, there was no need for such rudeness. We simply have no other options.
Also, I don't claim to have any answers to this. I felt, despite obvious dangers, it was fair gamble to field Frings as FB. And again, if we would have used some of our chacnes, it could have worked out.
But now we are looking at the ruins of this still young seasons - having to deal with loosing three important matches - no EL/CL for us, no Buli 5th rank and no DFB cup. That is quite a blow. I hope the team will recover from that.