Does she seriously think that WMATA should set a course for the next 25 years and then not revisit it? Even if unexpected crises erupt in the meantime? No one anywhere does that. It's all good and well to have a long-term vision but strategies and tactics should be revisited as circumstances change. Organizations need to be flexible and responsive -- although those are not characteristics unions are known for.
Re: Headways
Everyone would like more frequent service but the first order of business should be increasing the reliability of existing service. And, reliability is more important during rush hour. That's when being on-time is more important to most people (to avoid being late for work) and that's when there are fewer practical alternatives and less slack in the transportation network to deal with issues.
That said, reliability is also very important during track work on the weekends. If there are going to be 20 min headways, make sure you stick with that and stay on schedule because otherwise the system is totally unusable during track work.
Increasing reliability is partly about catching up on deferred maintenance but also about hustling and having a sense of urgency about your mission like the postal service. With funding constrained, perhaps there are techniques from the reliability engineering field that can be used to focus limited resources on that aspect.