Many advocates of the A3 process, John Shook among them, swear by hand drawn A3s, and so do I, up to a point.
It's about the creative right brain, really. Numbers and computers can be so limiting. Better to draw stick figures and scribble problem statements in long hand script. Use pencil, naturally.
But one of the major objectives of drafting an A3 is to create systems of measurement. This implies that there will be, at some point, the creation of a database designed to contain data. Despite the obvious appeal of hand drawn graphic images and hand lettered text, there is a very practical consideration not only of data collection (which can be done fairly easily by hand) but also of data processing.
While one can make the case that recording data by hand is best--and I can think of many situations where this is true, on the manufacturing shopfloor, or the shopfloor of healthcare, for that matter--we must, at some point, "enter the data," be it into Excel or Oracle or SAP or EPIC or whatever, where data will be processed according to automated algorithms, simple or complex.
My point is that even simple data processing is not, let us agree, done so easily by hand. For this God created Excel (and other spreadsheet programs). The days of the slide rule are long gone.
Why not address the issue head on? I currently recommend to my clients that they build Excel databases and charts before drafting their problem statements and target statements. While this is often met with resistance, it pays immediate dividends in the form of clear definitions of both problem and target. It also establishes a practical framework for measuring progress towards the goal of improvement.
The alternative is fuzzy thinking, no matter how beautiful one's charts and graphs.