I am a big fan of drumbeats. People are busy and it's easy to miss one large product announcement and even if your audience sees the announcement, it's easy to forget about it.
My favorite packaging approach is to have a broad theme ([your service] keeps getting better, a commitment to security or performance, helping your audience do something better, faster, cheaper...) and then announce each small enhancement as it comes.
Say you have 5 small enhancements over 12-15 weeks. Start with announcing the first enhancement on your blog/email/social channels as part of a broader theme. For the next enhancement, reinforce the theme and call back the previous one... and so on for the next 2. Then for the final one, you could consider doing a bigger announcement via press/event to show constant progress.
This way, you get to tell your story multiple times, gain credibility for your theme, and improve your SEO juice for each enhancement... no one feature or subfeature gets burried in one bulky announcement.
Think of this as an "Agile Product Marketing" concept.