by Chazar » Tue Jun 18, 2013 8:43 pm
Yes.
Check the version news for version 0.9 since then UL is added to strength to ruins, so scouts, crusaders, wizards and ghost get a slight increase too, but their UL does not stack with the hero's UL, only a unit's own UL counts. Since 0.9, ruins no longer count as city terrain either, but they still provide +5 wall bonus.
So low-level Barbarians should be cautious against Rangers and Paladins defending a ruin.