My father has an HTC Incredible, and a major source of frustration is that the Sense lock-screen uses a swipe gesture to unlock, which for some reason is very difficult for him, especially when trying to answer a call.
I can turn the lock-screen off, but this results in the answer and decline call buttons being active immediately, which could result in premature answering, or accidental hang-ups.
I've also looked into some of the security options, as replacing the swipe gesture wholly with a short PIN or password (skip the gesture, only enter the PIN) would likely solve this problem. Losing the ability to answer from he lock-screen is acceptable. Unfortunately, these options still require the gesture to get to them on Sense (and on my own phone running CyanogenMod, as well).
The hardware is out of warranty, so I can root and flash CyanogenMod if I need to lose HTC Sense to do something.