I personally would use MUC/FRA/VIE due to Schengen - much easier to tranist. I will transit LHR so not against just if all else is the same.

As it relates to the dynamic award pricing it may be good to book the low mileage redemption and have an extra day somewhere to adjust the body clock.
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I have found both LOT and TK to be great airlines. Have stayed in both WAW and IST and found that good as well.

I am all about the lie flat seat for TATL.

Edit - I personally try to avoid EWR whenever possible. Always delayed, although in fairness my flight through there last month was on time.