The ability to lob Jacks to the back of enemy bases is a cool strategy but I feel it needs tweaking; currently it is too easy for them to hit the back line without a downside as units that exit the map boundaries come back in guaranteeing you the ability to land along the enemy back line. I feel there should be a punishment and some degree of skill / trial and error in the form that any jack thrown too far disappears off the end of the map (wreck metal could disappear or appear at edge as further liability of poor execution).
Possible solution;
The jump ability to only be available while on the ground or under a certain height (else they jump just prior to going beyond the back edge of the map.
Anything going past the map boundary over a certain height not to elastically return to the edge of the map, i.e. units fighting on the edge pushed by newtons don't just die etc.
Alternative solution;
Jump velocity upwards takes into account the falling speed. I.e. if launched high enough, jumping may only slow the fall rather than jumping up again (so there is a large amount of fall damage). Physically if a jump can jump x height while stationary on the ground, if the unit is falling at a great speed and jumps it should not be able to achieve x height from the initiation of the jump. This may kill the throwing jacks strategy which is pretty cheesy anyway.
Always easier to say but the strategy seems too easy with great payoffs and the counters to this are overly expensive when looking at the ares required to cover vs the ability to fire jacks along the full back line of bases.