As others have said check your recent flights for the booking classes. wheretocredit.com might help. But if you can achieve TK Gold that would surely be better than LH silver.

I'm not sure what customer service / support is like with LH but it can be a battle at times with TK. It's often better if you have a good local sales office.

If Gold is your main driver have a look at the new HSBC Star Alliance credit card. It's not yet available in all countries but it gives you a fast track to gold. Also A3 might be worth looking at particularly if you fly to Greece each year. Asiana was also pretty generous but they're in the same boat as SK and I presume will leave *A soon.

Yet another option is ditch airline loyalty altogether, get an Amex Platinum card. It gives you lounge access (mostly priority pass which is less than ideal), but of course you don't get luggage, fast track etc etc. It also has a host of other benefits handy for a frequent traveller. They offer good discounts on business class airfares through their travel service and of course you're free to fly which ever airline you want thus potentially saving money.

Just some options to consider. Having said all that I'm TK but channel excess miles beyond requalification to another program and have an Amex Platinum for those times I fly with a different alliance.