Yes perhaps there is a point not to write a letter also, but equally valid is the point that no arrivals lounge is provided for inbound business class passengers. As I said, this differs from my overall experience flying in international first and business class. Also in the states, if they let you in to a lounge I don't see them then finding and throwing you out. Finally there is some point that the travel industry should be accommodating and helpful to its customers, and the Oneworld web site implies that they will do this, although it is just PR, they say thye purpose of the alliance is to make your travel easier, etc. Perhaps the letter should be more like "AY doesn't have business class lounges for arriving pax, so I will fly another airline," and maybe I will not even mention the experience at HEL, and again in the future I will just buy a refundable one way ticket etc.