I think it will be very important as well and something many will really love/hate about it, the balance between getting a creature to low HP and immobalized while trying to keep your creatures alive with heals while at the same time trying to catch it hoping it won't run away having made you waste a lot of mana and ammo on failed attempts will be interesting.
Thankfully the players won't find out what they missed out on (its stats) if a creature flees, we're not that evil. xD