Are TTVs too powerful or too easy to make multiple of? (classic)

[valtsu0]

I feel like TTVs never lead to anything else than early shuttle calls. While one is usually repairable the bomber probably gets at least a few off. Maybe TTVs would be more interesting if there were an actual chance at defusing it?

It's really rare to see any the other explosives. Cambombs are empty prank ones most of the time and pipe bombs aren't exactly popular either.

What do other people think? Should TTVs be changed or are they fine the way they are now?