The limits sound fair anyway, but I see external researchers (and even community members interested in historical data) using this tool to collect very long data series.
I think that use case is out of scope for Wikimetrics. It's getting dangerously close to using Wikimetrics as a general data platform or service, rather than sticking to getting human-readable results for standardized metrics. It's okay to go back months or years in time, but not simultaneously at a level of detail not interpretable except with further heavy processing of the result.