Whom would they replace him with? Paddon has comparable (slightly worse) results on gravel this year and he has never shown any good speed on tarmac.
Sordo said he doesn't want to do full season again.

Only clearly better option could be Lappi, who is still quite untested and unlikely to want to change so early. Latvala as mentioned is doing even worse than Mikkelsen this year and was also worse in 2016 when they were in same car.