Not so much a classic mode as it is just imbalance within a games rule set. But I always thought that blue Trolls light on Medieval Madness is - rediculous.
Unless you have Trolls in multiball madness or get smack-a-troll mode (not available in tournament mode) you will never reach it. The Troll build targets are just too dangerous to manage a stratigic progress for that far out reachable goal. In contrast Trolls in multiball makes the goal much easier to achieve.
Also the troll bombs are similary too hard to achieve once trolls are lit.
I believe they should have made the troll build targets active during multiball.