When designing the layout of the Sitefinity Forums we opted to leave spaces between the lines so that forums are easier to read.
We are sorry to hear that this creates problems for you and will need to know more about your experience :
1) Why do you find this layout fatiguing?
2) What spacing would you rather use?
This is the first time we receive such feedback and would leave the discussion open.
Probably other users would like to comment as well.
All the best,
the Telerik team