Even though time-wise, far more than half the season elapsed, we all know that the last two months before the Tony eligibility cutoff are typically packed with openings, and the planned 2020 spring season was no exception. In the Best Musical category, for instance, only four musicals are eligible out of eight that would otherwise be eligible had the season carried on as usual. None of the three musical revivals are eligible. So, while not a half-season in terms of length, it's certainly a half-season in terms of openings.
And yes, I'm aware that there are pages and pages of rules regarding Tony eligibility and voting. I'm also sure you're aware that nearly every year, the Tonys announce significant changes in their rules--be it eliminating categories, reinstating categories, eliminating a large number of eligible voters, or shifting eligibility requirements, all those things have happened in recent years. And the categories will be de-gendered in time, the only question is if they will do it now, ahead of the curve, or in the future, acting behind the times. Many prominent regional theatre awards (including DC's Helen Hayes Awards and Chicago's Jeff Awards) have already made the move to de-gender acting categories, and more and more are doing so each year.
As for your concerns about them rushing to make a last-minute change, by the time the nominations are announced next week, it will have been more than seven months since the season abruptly ended. No, they shouldn't have to hastily make a decision within the next few days, they should have "examined the ramifications," as you say, over the last seven months. When I said they should "try that out" this year, what I meant was not that it's a simple little change, but when in such an unprecedented time which requires the committee rethink major questions--including whether or not the awards should happen this year, which was not a given--it's worth reexamining other rules, like the ones regarding gender in acting categories, which suddenly seem small and solvable in the wake of the current moment.
What better time to make such changes while on a hiatus? Because inevitably, very soon, a person who identifies as neither male nor female will be giving an award-worthy performance on a Broadway stage, and the Tonys will have to reckon with their system and make changes. Across the nation, theaters and theater workers are spending time during this hiatus to figure out how to make the industry more inclusive, welcoming, and fair. There's no reason the Tonys shouldn't be doing the same.