It looks like the course has now been extended! I'm not sure if it reaches the whole way to 5000 words or not, but I'm just over 4700 and it is still feeding me new words.
I do appreciate the addition of new words. 4000 to 5000 is a substantial difference in vocabulary, and I have noticed some of these words showing up in daily usage, and found some of them useful when trying to express ideas myself.
In the end though, I think the Spanish course is already more-than-good-enough for me to use it as a booster to get me most of the way to where I can go the rest of the way through immersion.
I would really like to see Lingvist turn now towards adding more languages. I have not found any other tools that are as effective as Lingvist, and I'm close to exhausting it for the three languages I want to learn (Spanish, German, and Russian) on it...but there are other languages (Chinese, Hindi, Portuguese, Japanese) that I would really like to learn, and that are not offered yet.