as difficult as

[AirbusA321]

Are they all correct and are there differences in meaning?

The exercises...

were as difficult as expected.
were difficult as expected.
were as expected, difficult.
were like we had expected them to be: difficult.
turned out to be difficult as expected.

 

[emsr2d2]

Are they all correct and are there differences in meaning?

The exercises...

... were as difficult as expected. :tick:
... were difficult, as expected.
... were, as expected, difficult.
... were, like we had expected them to be, difficult.
... turned out to be difficult, as expected.

See above. With the addition of my punctuation, they're all correct. The last four pretty much mean the same. The first suggests that you already had an idea about the level/extent of difficulty that would be experienced.