According to the developer's worse case scenario, in 3 years, the table will be 12 GB.
In just 196 days after deployment, ORES table (on enwiki-master) is:
-rw-rw---- 1 mysql mysql 6.9G Mar 6 20:49 ores_classification.ibd
And it is crossing the 100 million row mark. It is alarming, as we are on the "3 times worse than the worse case" scenario. It would be nice to have plans for archival, purging or partitioning.
The table size is not a concern in other wikis, like wikidatawiki.