We can insert 16 columns and row not a problem.
If you add more row then performance get slow.
Maximum Limit for Rows or Columns of Data
go to Analysis>Table Layout>Advanced > Rows / Columns (Maximum levels of row labels) can be increased to 16.
We can put many number of sheets there is no limit.
But if we put more and more in the field the worksheet looks like a mess so
we can use measure name and measure values.
If you use Measure names and Measure values it will not look a mess.
But if you just put the fields in rows it will not look good.
So you can use measure names and measure values.
Vishal- Edgematics Technologies