It is impossible to answer your question without deeper analysis and more data. The above CTR is just below 6% and whether this is good or bad depends on the position in SERPs.
Also, you are talking about converting impressions into clicks, but you are not saying what is your aim after the visitor clicks through to your site - what are your *real* conversions? That is, what do these visitors mean to do when on your site - buy something, click on ad or you want to have traffic just for traffic sake (in which case you may be wasting your bandwidth with wrong traffic).
we have one account at around 370,000 page impressions at 22,000 clicks for the month
This implies this is the summary for the whole site, which means that the information is skewed. You should drill down and analyse which pages contribute to most clicks, what is their impression and CTR rate and for what keywords they rank and where. Only then you could conclude whether the better titles (and on which pages) will bring more clicks. For example, if a handful of pages have a high CTR and reasonable ranking and they are disproportionally contributing to CTR, whereas the rest of pages are not ranking well, then you may not see great improvement from improving titles and descriptions as the increase in CTR in low ranked page may not be significant enough to the overall site.
On the other hand, improving page titles may not only improve CTR, but in some instances they may improve ranking in SERPs so you may have some wins here. But equally, changing page title may also result in drop in ranking for more searched keywords.
As you see, your question does not have straight forward answer and the best you can do is thorough analysis and then perhaps single a handful of pages, do your changes and monitor the results.
