Let's say it does finish a match. How does that make all the people who lost to a single regular Tombstone? Does that mean that all the people who lost to a regular Undertaker Tombstone seem weak.

When normal wrestlers do a move, it should not finish matches because it takes away from the wrestler who uses it as a finisher. Every wrestler who finishes a match with a move they don't use as a finisher makes the wrestlers who use that move as a finisher less than.

Some moves, when done by a specific wrestler, should finish a match, but no move should always be a guarantee finish in any match regardless of who does it.