So in my last post, I alluded to how I was consolidating all of my 'thief-type' abilities (move silently and hide in shadows) into one 'sneak' ability. Today, I was messing around with 'hear noise' and 'spot', and realized that these are the opposite of the two thief abilities, and could likewise be consolidated into 'sense'.
I DON'T want to get into contested rolls, but I'm fine with the 'passive' ability affecting the 'active' ability. For instance, as a thief you have sneak equal to your level +2. A stoutling gets an automatic +4 to sneak. Let's put it up to the Bilbo test...
Bilbo has sneak +4 as a racial ability, and the one ring grants invisibility +15, giving him +19 to sneak in ordinary circumstances. Unfortunately, sneaking into the abode of Smaug isn't ordinary circumstances. Smaug, as an 11 HD dragon, has sense +11 (I'm giving dragons sense = to their HD; simple math that makes sense to me). Bilbo's +19 has now been reduced to +8, and adds are good that - even though Smaug cannot see him, he's still going to know he's there.
I am tempted to only give this bonus while the dragon is in its lair (since Smaug scours the mountain looking for the dwarves and cannot find them). It seems reasonable that a dragon is always +2 to sense, but gets its HD bonus instead when in its lair. This keeps me away from any sorts of contested rolls or 'you succeeded with your sneak but he succeeded with his sense, so now we see the margin of blah blah blah...'.
Is this too much combining of abilities? It feels right to me, but what do I know?