Currently you cant place a fully complete team down in OW due to a cap on how much mastery points you can use.
I understand there is probably good reasoning behind this (assume its to keep the need for consumables high) but it feels bad when you get towards the final form of the team you are building and you cant even use it due to the mastery point cap.
I'd suggest what ever reason this is in place for, doesn't outweigh the negative feeling of players wanting to use their full team and ranger gear, but cant.