I think the average data team at a startup using something like Redshift/BigQuery/Snowflake is using window functions quite extensively when writing analytical queries/building data pipelines so I'm surprised to hear you haven't see much customer demand for them.
If you trying to wholesale replace a "traditional" batch oriented data warehouse like the ones I mentioned above I think building support for window functions would be essential.
If you trying to wholesale replace a "traditional" batch oriented data warehouse like the ones I mentioned above I think building support for window functions would be essential.