MHW doesn't stand a chance in the long run. The legs of Monster Hunter games are not strong at all.
Legs of mainline are pretty strong though. They usually stay in the top 50 until a new game is released. Splatoon 2 should be higher than MHW though. The fact it isn't a surprise in of itself.
Far Cry 5 had a pretty good debut. FC4 only did 36k on PS4 (did just over 50k FW on PS3/4), so that's a nice bit of growth for it. I'd be interested in a SRW comparison if anyone has one. ~140k sounds ok but not good. Also, for a re-release Siege is doing pretty well. Should be another easy 50k for them.