Quick tip: If you already have PyRevit installed (which is such a useful plugin in so many ways!) then you already have some text-change options. Maybe not everything you want, but it just might suffice.
Select one or more instances of text, then choose PyRevit->Modify->Override and select Override Text from the dropdown. From here you can convert the selected text to either of these three options:
EVERYTHING IN UPPERCASE
everything in lowercase
Everything In Titlecase
Another tip: I have this 'override' section of PyRevit mapped to these keyboard shortcuts, which don't conflict with anything predefined by Revit:
OD - override dimension
OT - override text
OV - override color
That last one, override color, is an incredibly fast way to colourize something. I can select a couple of walls, hit OV, choose Red, and voila! Easy to make those elements stand out in a hurry.