Catja's answer is effectively advocating that the block is outright removed and I wanted to simply garner Community opinion on whether that is the right course of action. To that end this is a counter-argument saying that the block should remain in place until such time as an effective permissive, yet still spam-blocking, alternative can be put in place.
Note: I am generally in favour of the removal of the block, as no language or person should feel that they are unwelcome here and in its current form the block is more of a hinderance than a help, but it needs to be done in a considered and deliberate fashion.
As such this answer is intended to play the devils-advocate.
Those parties choosing to bombard our site with spam are an ever present background hum of activity on not only the Stack Exchange group of sites but the internet in general.
One of those groups are a set of Korean language spammers who are technologically savvy users who are able to evade conventional spam-fighting tactics such as user and IP blocks and several previous incarnations of regex based filtering (might have previously been removed and reinstated, but I do not know) as evidenced by the fact that attacks persist even when fed into the existing spam prevention system by both community members and moderators alike. This puts them above the more mundane spammers that frequent our site to advise us of their nice floral boutique shops never to be heard from again.
These attacks have happened before ,  and we have tried to relax the system after some time only to be met with another influx.
Lacking a system that is flexible enough to meet the demands of the community I would argue that the current block, while heavy-handed, is necessary.
Unless the current block can be relaxed while simultaneously retaining a sufficiently strict edge to prevent future waves I do not see simply removing it as a solution.
The current regex based system may not allow sufficient flexibility to suit a large number of use cases. If it is not up to the task then perhaps a new system needs to be put in to use.
As a primarily English speaking site we already enforce rules that the majority of a post should be in the English language, but there will always be situations where users need to use their native alphabet to demonstrate a problem correctly and succinctly. We shouldn't be afraid of one set of bad actors
Such a system was requested in the past Meta SE: Enable a percent-based block of CJK characters on Travel so this isn't a particularly original request, but it is a request nontheless.
While I am willing to relax again, I would prefer that it be done with a goal in mind: at an absolute minimum it should be to finally give evidence of whether or not enhancement is needed to the current content filtering system. If the spam has subsided then nothing needs to be done, but if it happens again we need to know that something will be done going forwards.