(I was thinking hard whether to mark this as improvement or bug. I decided it's a usability bug.)
When you open a collection, you don't see the collection contents (items). You see a list of possible views (Browse by: By Issue Date, Authors, Titles, ...). For first time users, this is confusing (they don't see content immediately) and for regular users there's an extra click required every time they open a collection . Confusion of first time users is further aggravated because they see a list of recent submissions which looks like they're looking at content, but this not complete paginable content and complete content in this format (reverse chronological by submission date) is not even available as an option. The last issue is that it's not even easily visible how many items a collection contains before selecting one of the views.
I'm sorry to sound so harsh about this, I know it's been always like that in DSpace so some might consider that a feature. But I've seen first-time DSpace users confused over this again and again. I think this is a major usability problem.
1) Pick a default (but configurable) view for collections
2) Remove "Recent submissions" from collections
3) Add "By submission date" as a view - complete with pagination and item count. This can be even made the default view.