The nature of the errors are different, it's difficult to compare falling vs. UR directly. You could fall on a fully rotated jump, which means you have mastered the jump (e.g. Quad Flip) whereas the UR could mean the skater is not even close to mastering the required rotations to call the said jump a Quad or Triple. The latter could be a very serious consideration given that a Quad Toe is worth 10.3 whereas a Triple is only 4.1 If UR is not severely penalized, there would be a surge of bogus claims re: skaters who claim to be able to land Quads for example. Using an example, if a skater severely UR a Quad Toe attempt, it wouldn't be fair to give him 10.3 of BV - 3 for GOE - 1 for falling because that would equal 6.3, a value greater than the Triple Lutz even though the Quad is more like over rotated Triple Toe. If so, a program could be filled of bogus Quad attempts with 6 or 7 falls and still end up having a total TES equal to 6 or 7 Triple Lutzes combined. Clearly, I don't believe you think that makes any sense.
Sometimes a fall isn't as bad it seems. The encouragement should be focused on getting the skaters to learn the proper technique and fully rotate their jumps as opposed to encouraging gaming behavior. So to answer your question, yes, I think UR can be a much more serious problem than a fall.