There are a couple valid aspects to consider before answering this question.
First, how many hours are necessitated to administrate the will? (How lengthy is the will, how many prerequisites must be fulfilled/monitored by the beneficiaries, how many beneficiaries are there? Does the executor have up-to-date contact information of the heirs/heiresses, or will investigation be required? Etc.)
Secondly, how large is the estate? How much of a percentage is the fee in comparison to the sum total value of the willed estate?
I think in some circumstances, an executor's fee is more than reasonable. There are attorneys paid in the millions to "execute" a last will and testament.