Think of MA furballs and how they mostly take place on the deck. Very few players have the willingness to go head to head at 12k or higher unless they have tactical numbers to hide behind.
I've been in one fight in WWI-Arena that started higher than 100ft. It was at 2k over the cons swirling hoard below us. With that much air under your WWI kite you can recover from spins and bad wing over stalls unlike at 100ft where half of our kills are the con stalling into the deck. So we went round and round up and down until I got a strong guns solution and my advisary pointed his nose straight down and ran to his 100ft high hoard.
Being the only green guy for 2k around now at 1k alt with a new hoard approching from 2k out to support the hoard just under my feet, I began briskly peddling my whirlygig in the direction of my slowly creeping countrymen. The whole time I was strolling away from the hoard, the hoard was strolling with me peppering my kite from 800 back enmass. Around the time I stopped counting holes in the fabric and finished admiring the wood through the fabric shreds, the hoard behind me all broke and headed back to their bigger higher hoard because my six countrymen were 500ft higher than them.
I really wonder if fights in the WWI-Arena will ever take place at historical altitiudes. So far I know more about what the tree trunks in the WWI-Arena look like than I know about ACM flying the WWI kites above 100ft. Lets see what I remember so far.....swirl left, swirl right, wing over wing over, look out for the ground, swirl right, swirl left, look out for that tree...hmmm nice bark on that trunk...wing over, wing over, dangit he stalled and flopped into me again............