I know: as the Damsel, you have the normal weaponry, don't take as much damage, shopkeepers are kinder to you, and you can't get killed by the ghost.

But every now and then, Spelunker grabs you and either carries you to the end of the level or sacrifices you to get himself some spring boots.

Haha, yes. I recall the first time I was trying to bomb-snipe an angry shopkeeper, while holding a damsel.

I did manage to chuck her away, but at that point in my Spelunky career I was relying on Damsels for health so I felt sorry for the both of us. 

Well of course, she also runs slowly and can't jump, so I don't know how true to her NPC characteristics we want to cleave. 

Oh, ah, also, don't know if you'd call it a mistake, but I once got an intro message along the lines of:

AS I RECALLED MY FATHER'S LAST WORDS
I SPOTTED THE CAVE'S ENTRANCE
AND THOUGHT OF HER.

I thought it sounded a bit odd.

At the end of the Black Market massacre, I approached the exit door, which was right next to a spike pillar. I hit the exit holding up, so I had already started to go through it when the spikes went off, but they hit me—sort of. I heard the sound you get when you take mortal damage while holding the Ankh, but I saw the end-of-level screen like normal. On the next level, however, my Ankh was gone.

(I was the Tunnel Man at the time)

I was pretty shocked when I unlocked the Tunnel Man; infinite mattock? An only slightly-less-useful-than-Spelunker's attack? He is far and away a simply better choice for getting money, doing a speedrun, some of the challenges...

How about this: the game records different high scores for each of the characters. On top of this, something could be done to the Damsel character to make her different from the others; for instance, she could have no weapon. In this way the game would immediately have three different difficulties built right in: Easy (Tunnel Man) Medium (Spelunker) and Hard (Damsel). The different sets of high scores would prevent people from just ignoring the weaker character(s).

My reasoning is, even if you start adding little changes here and there—making the Tunnel Man start with no ropes or bombs, or making him take more damage, or whatever—the changes are eventually going to feel too arbitrary, and no matter what, with long playing one character will still likely turn out to be superior to the other, and thus the other will simply be ignored.

Does this seem like a reasonable idea?