It's a bit old now this question, but I came here via Google, and someone else might also. My solution was to create a Preflight profile (Acrobat 9 Pro) which errored on font information. Clicking on the font name in the results then jumps to the page and highlights the text. Downside is that you get a list of all fonts on all pages organised by page rather than by font name, but it provided a solution for me.
1) Create a new Custom preflight profile
Advanced|Preflight|Options|Create New Preflight Profile
2) Give the profile a name (Fontfinder, say)
3) In the left window of the dialog click "Custom checks"
4) In the right window of the dialog below the blank box click the plus symbol to create a new check and include in current profile
5) Click "text" in the Group, the bottom property is "Text size". Select this and click "Add"
6) The pane below now has more options. Click on the drop down options probably labelled "equal to" and select "less than"
7) Enter a large value in the Number field. I entered 500
8) Top left of the dialog when check fires report as... and enter something like Text size 500 pt or less and click OK. There should be a new custom check in the pane with a red cross beside it. If the cross is not red, click on the check label, and select "error" below the pane
Repeat the steps above for another error check, but changing the option for 500 to "greater than or equal to", and Check fires report as Text 500 pt or greater
9) Click OK in the Edit Profile Dialog
10) Run the profile on your PDF
I set the font to error on a large point size so that all of the errors would report in a group. The second check is simply to catch any font larger than that. I suppose you could check for pt size 50000 and have the same result.
Best Answer
The editing capabilities in Acrobat DC are improved considerably over Acrobat XI, and that may actually be worth the upgrade cost.
However, changing fonts in the PDF may cause problems, unless the run-length of the replacement font is exactly the same as the one of the original font. Otherwise, you may end up in tedious adjustment tasks.
Therefore, it is much better to do the edits (which include the font selection) in the original document (and if you don't have it, but have the permission to noodle around in the document, export it to Word or so, and make the edits there).