Hi,
I do understand your wishes, but would hope that you might see that you provide a valid service and alternative to that which is being supplied by CCP.
One of the largest barriers to entry for the use of CREST or ESI is JSON. Many of the Google Sheets that use your API would be unable to retrieve data from these services because I am unaware of any ability to take JSON data and link it to a Google Sheet. If someone knows of a way to do this, I would be glad to hear it.
Another large inconvenience is CCPs insistence to not give us usable multi-region data. Looking at both CREST and ESI, I would have to make several requests (and custom code) to get the data I need, where your resource provides one complete resource.
In the end, if things are becoming hard for you to maintain, I understand the need to cut back. However if there is something I can offer you (assistance? code donations?) to keep things going, please let me know.