I'm interested to see how the K50 + WR kit lens feels in terms of weight. I've found WR to be invaluable. The peace of mind and not needing to scramble to put the camera in a bag is fantastic. And you can keep taking photos. Problem I have is the K-5 + 18-135mm combo is pretty heavy --> 1.2kg--feels like a brick, when you want to carry the least weight around while going out for the day. I recently commited a sin and bought a Canon 100D- at 600grams for body and kit lens (STM- so much quieter and quicker to focus than screw drive)--> it is very light and convenient to carry on the day out at the trails...but it rained every 20-30 minutes for 5-10 minutes- the light weight useless since was in my bag 1/3 of the time.
I think the K50 and kit lens is about...850 grams? Wonder if that makes a difference in the hand.
ps: I've been such a die hard Pentaxian the last few years you won't believe how guilty I felt when I bought the Canon. Took me a while to get over it!