As best I can determine, the delay is due to ArcMap querying Windows for the installed fonts. The more fonts you have installed, the longer that query takes, and that query is not cached (so every time you push Edit Symbol it happens all over again).
So I aggressively uninstall every font I don't use regularly, and repeat the process with every new software install. This can be a painful exercise as it's hard to determine exactly which fonts are in active use by programs and documents, especially if they haven't been used in a while. This is compounded by the fact that many programs, especially ArcMap, don't complain if they can't find the typeface they've been asked to use and will just silently substitute another one.
There are number of font/typeface managers out there, some are very good, and expensive, and many are just not. My current preference is for NexusFont, which is free, fairly feature rich and nimble. It does occasionally crash or otherwise behave unexpectedly. Of the commercial ones we've evaluated Suitcase Fusion comes out on top.
Whatever font management system you use, arrange your fonts in folders -- mapping, word docs, websites, etc. -- and link to the files instead of copying them to the Windows Fonts folder. This facilitates turning them on/off as needed. Here's how I have mine setup in NexusFont:
The numbers are bit faint in the screenshot, but hopefully you can see that the default set (that is, what was put there before I started managing the fonts) is a hefty 757 typefaces while what I use most of the time is "only" 170. I'm sure I could cut even that in half or more but so far I've lacked the willpower to analyse further. (That would make a great open source project, a public listing of all the required vs desireable vs fluff font files!)
Best Answer
you can work with the annotation properties like with a normal attribute table. So you can update your properties using the field calculator. You just need to know the exact string (or value), so I would first change one annotation manually in order to observe the right syntax.
EDIT : another approach for full control is to start an edit session, select the annotations that you wish to modify, and update based on the attribute window (on the editor toolbar).
If you select the annotation class name it modifies all selected items. Note that you need to press "apply" to actually change your annotations.
Another approach consists in using text formatting instead of annotation properties. This way you have all information in your text string. For instance :
that you can create with the filed calculator (python parser used here)