If an aggregate served a purpose beyond simple aggregation, that's one thing. But, to create an aggregate class simply to collect things ... that's the red flag. We already have something that collects things - an array. Unless you're spicing up the array somehow, there's no reason to create an additional syntax just to be more OO.

Some reasons I could think for creating an aggregate class:

• An iterator. Iterators are, at their base, arrays, but they often provide much more than simple iteration. I use them to provide a single interface into various forms of lists.
• A factory. A factory can also be an aggregate, providing both the ability to create and to iterate. This can be helpful.

Remember - we don't want to go the Smalltalk/Java route where you have a Collection, SortedCollection, Set, Bag, etc. Or, the C++ version where each of those are templated to comply with strong typing. Leverage what exists - don't reinvent the wheel.