Wade In is another situational event that only works well in very specific setups, so it's only worth playing when those opportunities present themselves naturally.  Trying to force setups to make Wade In effective is usually not worth the effort.

One of the scenarios where this card is usefull is when you try to apply sudden pressure with Nymira. For example, you might move her forward to use Ebb and eliminate a unit, attack another and set up for building an offensive Gate on the following turn. In that situation Nymira may end overexposed and Wade In provides survivability.  

When you draw Wade In,  evaluate the board and determine if you can set up a favorable scenario that turn. If not, it’s often better to discard it.