To me FOG works best if it is entirely open or heavily themed, but an in the middle choice is not as good as either of those.
On the periods: I think theming needs to be rather careful about what is in, so you either exclude certains armies (e.g. WftS only minus Magyar), or you need to limit army design which then limits army choice (Max 16 Cv + LH for instance). Either will create a good Dark Ages period for next year and I would thne bring my Vikings!
If period 2 was more decisive it would be because it was shooty vs shooty which does tend to get results as they can't run away from each other - I had 4 "results".
Steppes issue is a bit of a myth in my opinion as most of these armies are very hard to deal with by largely foot armies - even in a desert!
Rankings clearly work well ... authors scores very much in line with pre tournament rankings!!
Si