I personally like mixing the “packing of features into a big launch” and the “ongoing drumbeat”. What we did this year was choose 4 customer objectives for our product for the year and kick the year off with a campaign speaking to them and how they solve our customers biggest needs. We then planned one “big moment” for each objective over the course of the year, this would be a month when we would hit hard on this theme repeatedly tied to a major launch. Then, outside these 4 big months we plan a steady release of smaller enhancements, tying them back to our 4 objectives.
Ideally, it's a combination of the GM, product management and product marketing. The GM would set the overall business goals for the year or quarter including revenue. The PM often drives the product launch adoption and revenue goals for that product. PMM often builds the plan with the metrics to help back into those goals.
The important thing is that if you see a gap, make sure that someone is owning all of these goals, otherwise, it will be meaningless to have launch metrics.
I like Zach's suggestion of finding a good mix but there can be times when a larger story just has more impact. At the end of the day, the key thing is to think in themes, and how those themes are going to drive value and impact for your customers. If a feature or item by itself will have large impact, then why wait to share the story? But if that feature has more impact when wrapped up as part of a larger story, then packaging it as such. I wrote an overview of this very topic here: https://medium.com/@anandp29/launching-around-themes-277eb621dd62
This is a common issue with the prevalency of agile software development. I recommend bundling up several iterative features into a meta-theme and then building a campaign around it every 6-12 weeks. This allows you to blitz the market with a bigger message/story, and it creates an internal drumbeat of messaging that the marketing team can deliver on repeatedly.
I think you’re asking if it’s behind a pay wall and not just a free product? If that’s the case, you need material (video!) that can act as a demo, people want to see product, not just read about it. Salespeople who can give great demos and free trials are often a really effective a launch tool.