Sure, last 3 tools icons (or user selected 2 icons and current one) would be better. Just one click and no waiting for menu being displayed.
My suggestion works (or could work, if long press of menu button releases that special menu) for all readers despite having a pen or not. Yours only for pen enabled...
The best would be to implement your and my suggestion. It would dramaticaly improve workflow on all devices, despite a pen.
Why do you need lines, rectangles and circles? You can draw them by hand. It looks better (in my opinion) even in a presentation. But OK, different people, different tastes, different needs.
