I had game in an Arena. I was Teutons with a Briton ally, I had had Malay ally, but he was mostly fighting away from me, and doing okay. I was fully boomed, I had 3 relics, and 20 trade carts. (lots of miners, lumberjacks, farmers etc) So, gold was not a big issue. Plus, the gold mines had not run out.
My Briton ally had massed mostly Longbows. With full blacksmith upgrades (take into note the plus 2 melee armor the civ gets) I had massed Halberdiers (most of my army was Halberdiers, I didn’t want to waste all my gold) Teutonic Knights (two castles to pump them out), a small group of Elite Skirmishers to counter some archers units, and later I got some Paladins out.
I think they were bad. Because, the enemy would try charge at the Longbows and completely get shredded by my swarms of infantry. They were using melee units mostly. All that said, how strong are Teutons with Britons combined?