Irreversible deformation of crystals (and heterogeneous materials) is often characterized by random intermittent local plastic events being signatures of the criticality. It was also found both experimentally and numerically that the extent of quenched short-range interactions (originating from e.g. precipitates or grain boundaries) fundamentally affects critical plastic behavior. Here, we present that the presence of short-range interactions have a high impact on the weakest-link behavior. To this end, a 2D discrete dislocation system was studied which was found to describe the avalanche behavior precisely during single-slip deformation of HCP materials. Short-range effects are introduced in the form of point defects. Our observation is that systems dominated by short-range effects exhibit remarkable consistency with the classical weakest-link picture while if short-range interactions are absent, the weakest-link behavior is much less obvious. Based on weakest-link principles a dynamic length-scale can be introduced that characterizes the typical extension of plastic events. This length-scale is tied to the interactions involved: If only long-range interactions are present scale-invariance is manifested in the unbounded spatial extension of avalanches, whereas the introduction of quenched disorder localizes the events. The same can be concluded based on linear stability analysis which shows that plasticity occurs in form of the activation of vibrational modes triggered by external loading. By introducing short-range interactions the extended modes present in scale-free systems become localized yielding spatially confined plastic events. Thus, with the change of the dynamic length-scale one can explain the mild to wild transition of fluctuations in plasticity. These conclusions are not limited to crystalline matter, it can be generalized to other models of heterogeneous materials. We, thus, believe that it will be an important contribution to the scale-bridging in modelling plasticity. Furthermore, studying the vibrational modes may lead to novel approaches of predicting plastic response in heterogeneous materials.