If your star average goes below 4.5, put out a quickie point release. That would reset the reviews, and the review prompt would drive a 5 star instantly.
IIRC, I'd also divide all the users into buckets, and stage out review prompts by week. You never want negative reviews stacked alongside each other in the review list. Multiple negative reviews is the kiss of death for conversion - rank drop could happen fast.
By staggering review prompts, you'd get positive reviews rolling in every single week, with a surge up front.
Obviously, that doesn't mean _ignore_ the negative reviews. Those are generally critical product failures. That necessitates response. We'd group and measure review categories, and reach out to affected users to see how they felt about potential and shipped solutions. Product quality is step one on good reviews.
None of that means setting your business on fire because of negative reviews. At the same time it's a critical signal to be dealt with, there's an immediate business problem of minimizing or eliminating the impact of negative reviews.
They're two different swim lanes requiring two different processes.