Blowin' In The Wind Rhythm Guitar Lesson

The use of a constant strumming pattern like 'Blowin' In The Wind' does mean that you can go more crazy with the harmony.

The forward and almost aggressive sounding rhythm part Dylan use is very clever, by using this type of rhythm the half bar at the end of the song doesn't sound strange, it is almost as if the song is in 2/4 time throughout with its half bar rhythm pattern.

The feeling of moving on is never interrupted by the constant move to the IV chord and this half bar rhythmical pattern.
This supports the songs meaning of "Blowin In The Wind" or "it's down to what perspective you take" message the song carries. 

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Dynamics in a consistent guitar part

To vary this type of strumming all you can do is to dynamically change it.
You don't want to plan this type of changes, keep it improvised, your dynamical changes should be completely down to following the vocal.

The most difficult part to get right might be the dynamic consistency of the plucked bass notes, use the DIY TAB to fully transcribe the part, it is more logical than what the video may first make you believe.

When you play this yourself, aim to interact with the singer and possibly even the harmonica player, should you want to completely replicate Dylan's first recording.

Bob Dylan has performed 'Blowin In The Wind' for almost half a century now and many are the variations he has put it through.

You should do the same, keep changing, keep exploring.