I know little about economy but even if Marcinkiewicz had anything to do with it, he will never admit to it. Judging by his latest media presence, all he is interested in is fame at any cost.
Marcinkiewicz merely have any idea about banking sector or economy. His carrier in this sector started only because Kaczynski wanted to get rid of him from media attention. Somehow pathetic taste of many Polish voters find this guy to be "charming" and according to them this is enough to vote on such person! :) Kaczynski was afraid of being overshadowed by Marcinkiewicz. (I mean just PR, not political accomplishments)
Later Marcinkiewicz was sent to London despite that his English was rather pathetic and experience in this sector almost none. Clearly political decision. From this time banks from private sector are willing to be in touch with him (still popular politician, promising prospect for important post in the future).
This is ridiculous to blame him that his advices lead to profits for Goldman Sasch on the cost of Poland. Firstly, because he has little idea about the subject. Secondary, because Goldman Sasch has plenty specialists, people whom really know something about this sector.
Personally I find Marcinkiewicz to be very small and disgusting person. However I must admit that he has a lot of luck, incidental PM and incidental banker. In the same way how he was not real PM (Kaczynski was guiding from behind), he is not advisor for any bank. This is all about politics and stinks of corruption mile away.