You can edit a PDF to a degree with Acrobat and appropriate fonts installed on the system.
Acrobat will allow some text editing via its text tool. But there may be some (rather common) issues:
- The user will need the fonts installed. Relying on the embedded fonts within the PDF itself may often result in poor kerning or missing glyphs. Having the font installed will allow Acrobat to reference the actual font as opposed to embedded data if it is necessary.
- Positioning. Since names and titles tend to vary in length, it can present a problem when a name does not fit the allotted space for it. Nothing is going to "word wrap" and moving lines of text can be problematic. All names would need to fit the space provided. It is generally not a problem to change "Nick Cage" to "George Clooney". However, changing "Nick Cage" to "Mary Elizabeth Mastrantonio" can be a nightmare. This, in itself, is reason enough to stick to editing in Illustrator.
- Positioning Part 2. Contact information in my experience can be wildly different per individual. Some users want just a phone, email, and address on their card. Some users want home phone, office phone, email, address, cell, fax, skype, etc. So for most business cards it often takes positioning adjustments to get all that extra data onto the card. This will, again, be problematic using Acrobat. Again, a reason to stick with the current Illustrator editing.
- No type "tricks". Editing in Acrobat isn't going to allow you to pull off some minor "tricks" often used to get things to fit or look more aesthetically pleasing. You won't be able to alter tracking, kerning or leading for text. Sometimes all it takes is a minor kerning adjustment to get a name to fit a business card. You won't be able to do that editing in Acrobat. So, even 1 glyph over the allotted space will be problematic.
- Aesthetics -- Most clients won't watch things for aesthetics. They'll just slap on the change and run with it. They won't care about horrible kerning, a line of text that is too long and breaks positioning. An incorrect alignment, etc. So to maintain continuity between cards, it often means you need someone with an eye for the aesthetics, not just the text changes.
I have set up a few standard PDFs and have a client that uses Acrobat to alter text in the PDF when needed. However, this really only works well when what is being edited is somewhat standardized.
For example, in the PDFs my client edits, they are editing pricing. So, in all instances the text being changed is a maximum of 7 digits ($000.00), therefore there's no issue with line length and spacing. I merely created the PDF with the space needed for 7 characters. This is nearly impossible for business cards in my experience.
Ultimately for business cards, using Illustrator (or InDesign) is a better choice than trying to format a PDF for client editing. There are just too many issues due to the varying length of names, titles, and contact information on each card.