PipeDream uses the Desktop font in the formula line as it is a standard Window Manager writeable icon.
You can change the font to a more readable one using !Boot -> Fonts -> Desktop font. Maybe a bold version of a sans-serif font would help?
An alternative may be to put the caret in the formula line and press Ctrl+Enter which will bring up the formula in the multi-line formula editor window, which still displays using the system font.
You can also set the size of the Desktop font (slightly larger, not too much!) using the Wimp$FontSize system variable. Press F12 and type 'Set Wimp$FontSize nnn' (without quotes) where nnn is the required size in 1/16th of a point. So, for 14 points you'd use nnn=224. When done press Enter twice to return to the desktop, and you should see a bigger desktop font.
To make the change permanent, create an obey file with the above command in it and add it to the list of things to run at boot (Configure -> Boot -> Run). Alternatively, you can install a (third party) configure plug-in that allows you to set the desktop font size (amongst other things):
http://www.vigay.com/software/miscsetup.html(quoted from SEDev's post on Raspberry Pi forum)
I will look at allowing use of a different font if you wish.
Stuart