I'm old and have been around DC a long time. I was here when the Senators were here and during the wilderness years. It may not matter to the younger or newer fans but it'd leave a bad taste for an "outsider" to be the fist to have his number retired. I'm with VaRK and spider on Scherzer and others ... maybe .... someday.
I've been around DC longer than you I'm sure, and I have no such sentimental feelings about him being an "outsider". I'm just against retiring numbers in general except for extraordinarily exceptional players ... Ruth, Williams, Musial. Etc. What I like is when team simply doesn't reassign a number that a special player wore, for a long period. Say, 15 years. I think of the Redskins for example. Sure they've retired 9, 42, 44, 49 and a few others. (Very few. And actually I don't really know for sure if those have been officially retired,but those will never be reassigned.) But I think of 55. It was retired for a long period, but eventually reassigned. And nobody has worn 7 since 1985 but you can bet that eventually it will be reassigned. If a team retires every number that a favorite player wore, they'd run out of numbers (like the Yankees are doing).