Rad to hear from someone who's already been at LANDR. I was all FinalTouch last year and found the same... after mastering, I wasn't happy with the mix, and had to go back and tweak things... so I don't think that's particular to LANDR. Although maybe there is more of that with the approch of one stop mastering software than with the slap a limiter on it and crank the gain approach. Since limiter+gain will be adding the least color of those approaches.
Did you find your mixes got any better or you had less back and forth as time went on? or was it a random crap shoot every week? Were you using the low/mid/high setting?
It seems like my first mix always sucks no matter what. But there does seem to be a bit of a random crap shoot element to it. Sometimes I swear I'll tweak until I'm blue in the face and can't seem to get a mix I'm happy with and sometimes after a couple tries I'll at least get something I can live with even if I might still have some minor nitpicks. I've played around with the different low/mid/high settings a bit and sometimes I think mid sounds better and sometimes I think high sounds better. I also think ear fatigue starts to set in after awhile when you do a lot of tweaking and you really start to lose your sense of what sounds good at all, so I do recommend coming back at it again on another day, if you have the time what with those harsh WeeklyBeats deadlines and everything. 
