Is it bad style to include a list in an abstract?
One important thing to keep in mind is that the abstract is typically copied to various article databases, which have varying support for markup. As such, much of the formatting will not necessarily be carried over. That nicely formatted bulleted list which appears in the pages of the journal can turn into a confusing mess in online article databases. (e.g. It might lose the bullets and be smashed into a single paragraph.)

For this reason, it's generally recommended to avoid any special formatting in article abstracts - even things like italics should be kept de minimis. 

If at all possible, skip the bulleted list, and keep the list in plain text format. If you do want to keep the bulleted list, be sure to format the list entries such that things stay readable even if the bullets are removed and everything is collapsed into a single paragraph.