Ignoring for the moment the fact that Holy Strength can be identified by the i difference and the umlaut difference, looking at the titles at this resolution for other differences does not really help. Therefore, this is considered a difficult-to-spot difference. (German Revised on the top, German Fourth on the bottom).

Here is a zoomed-in higher resolution (1200 ppi) scan of two Holy Strengths (German Revised on the top, German Fourth on the bottom).

Still can't see it?

How about now?

It looks like the card designers raised the title text up just a few pixels in the German Fourth edition so the 'g' no longer rests on the card frame, but rather hovers slightly above it.

This does not appear to be confined to just a few cards. There seems to be a wholesale change in the position of the titles from German Revised to German Fourth.

Here are scans of Animate Wall, where the difference is obvious.

And a German Revised Jump, where both the 'p' and the 'g' are resting on the card frame...

...and a German Fourth Jump, where the letters are distinctly elevated.

Burrowing.

Fungusaur.

With some cards, it's not so obvious. Look at these Eye for an Eyes - or is it Eyes for an Eye?:

Or my second set of Eyes...(German Revised on the left, German Fourth on the right):

And some cards are even less obvious. A German Revised Cockatrice, where both the 'p' and the 'g' are both happily resting on the card frame...

...and a German Fourth Cockatrice, where the 'p' betrays the edition, but the 'g' is not distinctly elevated. Luckily, in this case, there is always the i difference to fall back on.

This difference in the position of the title between the two editions helps us distinguish 13 of the German Revised cards:

• Animate Wall (Mauerbelebung)(White).
• Blessing (Segen)(White).
• Castle (Burg)(White).
• Conversion (Umwandlung)(White).
• Crusade (Kreuzzug)(White).
• Disenchant (Entzauberung)(White).
• Eye for an Eye (Auge um Auge)(White).
• Serra Angel (Serra Engel)(White).
• Animate Artifact (Artefaktbelebung)(Blue).
• Jump (Sprung)(Blue).
• Burrowing (Wege des Maulwurfs)(Red).
• Flashfires (Steppenbrand)(Red).
• Fungusaur (Fungusaurus)(Green).

As you can see, for some unknown reason, the white cards seems to be overly represented in the g differences.

There are a few more cards that have a 'g' or 'p' in the German name, but I do not own examples of them, so I cannot verify the difference:

• Swords to Plowshares (Schwerter zu Pflugscharen)(White).
• Counterspell (Gegenzauber)(Blue).
• Primal Clay (Urlehmgestalt)(Artifact).
• Swamp #1 (Sumpf)(Land).
• Swamp #2 (Sumpf)(Land).
• Swamp #3 (Sumpf)(Land).