I don't doubt that the NHL wants to avoid a situation where Nashville has a ludicrous cap recapture scenario, but its worth noting that:
1) The NHL didn't change its rules, it modified a punishment levied (a lot more leeway);
2) A significant reason they did so is because Kovalchuk retired from the NHL; and
3) New Jersey still got dinged with cap recapture when Kovalchuk retired from the NHL.
Hell, according the Capfriendly, NJ STILL has the cap recapture penalty for Kovalchuk's retirement (and will continue to carry it until 2025), even though he's been back in the NHL for almost two seasons.
And its pretty unlikely that Weber would retire with only one season left on his contract, if he retires early, it would likely be in the 3 years left window.