Good plan - with one caveat:
Topbonus' earning rates for discount economy fares buckets on all partners are dismal - expect to earn nothing or 50% on most, including EY. Check the earning tables and compare with the fares you typically buy before committing:
http://www.airberlin.com/de-CH/site/...tner/index.php.
I credit EY flights to topbonus (we well as AB flights that don't earn well in AAdvantage) and the program does offer solid value for me.

As you say you're flying to the Middle East/Africa, I would also have a look at QR and Privilege Club.
Frequent Flyer programs across the board have implemented changes that reduced earning for cheap Y flyers - with the notable exception of AA at least for the time being. And I'm pretty sure the party there will end as well sooner rather than later....

And I don't think AB's days are numbered. When push comes to shove I'm sure their friends from AUH will find a creative way of injecting additional money.