One of the things I like about the free PAL tool, is that you can specify thresholds for each performance counter. Therefore, you can have a customizable red line which appears on your graph to easily tell you if your disk latencies are over 25ms or your free memory is less than 5% - for example.
I would like to see something similar on the Analysis screen on SQL Monitor. I would like to specify for each machine, SQL Server or Custom metric a warning threshold and a critical threshold. This makes it easier to troubleshoot performance issues as you can see at a glance if it's performing outside of acceptable boundaries.
I appreciate you can compare baselines and add additional metrics on top of the current metric you have graphed but that doesn't give you the immediacy that a threshold line gives you.