SOD vs TE

regarding TE-light
contentious option -- building the second level
imho, it's better not to have level 2 for Castle, Necropolis, Rampart, Dungeon, Tower,
than for this level to be built by the opponent for Fortress or Citadel,
and Conflux becomes outright imbalanced

Indeed contentious. For Castle you don't need to worry about returning for an upgrade - you grab Marksmen and you're off. For Stronghold building is extremely desirable - sometimes instead of fighting properly you're running around a bend looking for ore that was given up for Gargoyles. And for Fortress imho it's not critical..