Normally i'd argue that with Wemby they have shown they will almost always choose caution when it comes to his bumps and bruises. The fact he went through some amount of warming up and apparently ended it early supports what you said, though.In these 50-50 game decision situations (ie pain tolerance threshold), it is always left to the players to decide whether they could give it a go or not, Wemby clearly felt he couldn't..
That being said, in terms of seeding we should probably come to terms with being the 2 seed, which is still amazing. I would be surprised if OKC loses >2 more games this season at this rate and looking at their schedule. Luckily with how seeds 3-7 are so tightly compacted record wise it will be an absolute crap shoot as to who ends up where. 1st seed could easily get a Denver/Minny winner in round 2 just as easily as the 2nd seed could.
Getting Wemby to mid April healthy is the priority now.