Hide columns without screwing up the table!
This one seems like such a no-brainer, but it has received no attention (apparently) from MS. Just make it to where you can shrink a column to hidden in the reporting and NOT have it screw up the table by wrapping the headers (and other odd transformations). This has come up many times in creating reports and I have either had to figure out complicated workarounds, or just give up. You should be able to set a column size to 0 and not have to deal with the repercussions of it totally running the reporting. Please!
Billy Moran commented
And/or, as this comes up for me most frequently with trying to hide certain columns in the Total section, make it to where you can select if you even want to see selected columns in the Totals. So you could turn off individual columns in the totals (% of row total, for example).