It would be really useful to have a per-collection setting that caps how many products a collection page displays, e.g. a "Maximum products to display" field.
Our seasonal and "instock" pages can run to 2,000+ products, and there are cases where we'd want to limit that - both for performance (especially on mobile) and for curated/campaign pages where we want a tighter set rather than the full catalogue.
The other reason is that ALPs are currently our only route to a limited set, and they come with trade-offs: they cap at 100 products, don't display coupon code promotions, and have less effective filters. A capped collection page would give us that tighter, curated set while keeping full collection-page functionality.
Ideally, this would be a numeric per-collection value, enforced server-side so lazy-load stops once the limit is hit. Default unlimited, overridable per collection.