I've never been a big fan of Canon's EF-S 18-200mm f/3.5-5.6 IS (terrible zoom creep, dust collector, not all that good optically) and would very much like to see a replacement, which I think is long overdue.
Japan Patent Application 2018-54990 shows another optical formula for an EF-S 18-300mm f/3.5-5.6 IS.
We believe this lens will be coming some time in late 2018 or early 2019.