EP always has some great ideas. Here's something I random-stormed.
Difficult terrain costs +1 additional space to travel through (so, 3 spaces rather than 2 for standard difficult terrain).
Trap terrain deals an additional +1d6 (per tier?) damage, due to not being certain how it's going to strike.
Cannot negate flanking from foes. Or when foes do flank, they gain +3 to hit, instead of +2.
May not be able to avoid opportunity attacks.
Lurker foes gain additional +2 to +5 bonus on Stealth check effects.
Hidden or invisible foes gain no bonus, particularly.
But moving silently foes might gain a specific bonus.
Perhaps gains Tremorsense 1/tier.
Grants combat advantage against ranged attacks only.
Difficult terrain costs +1 additional space to travel through (so, 3 spaces rather than 2 for standard difficult terrain).
Trap terrain deals an additional +1d6 (per tier?) damage, due to not being certain how it's going to strike.
Cannot negate flanking from foes. Or when foes do flank, they gain +3 to hit, instead of +2.
May not be able to avoid opportunity attacks.
Lurker foes gain additional +2 to +5 bonus on Stealth check effects.
Hidden or invisible foes gain no bonus, particularly.
But moving silently foes might gain a specific bonus.
Perhaps gains Tremorsense 1/tier.
Grants combat advantage against ranged attacks only.