Well, the authority (in that case the german LBA) does not approve an alternate method for smallish jets (737s) though. Therefore we have to comply with the required missed approach climb gradients.
And if we can't change the required climb gradient by using an alternate method there is only two other things we can do if we find ourselves unable to comply with then. However landing climb performance is a dispatch issue and has to be checked during planning and before takeoff, therefore it is highly unlikely to find oneself in that situation.