I understand that change of pledge would broaden what people (old, young, those with no income currently and working folks) can do. However. current GWWC pledge is more specific. It specifies the percentage of donation, 10%, which is measurable and can be used as a benchmark. People with less income like students are welcomed to donate less than 10%, say 5%.
Although the proposed pledge states the ultimate goal of ultraism, it lacks measurement as in how people make efforts, e.g. donating, volunteering? It is possible that some people take a vague pledge but do nothing because they could simply get satisfaction from taking a pledge and then think they indeed contribute (by just saying that "I'm going to...") But effective altruism and GWWC are more about action and what we really can do and will do to improve our society.