In order to obtain a realistic 3-dimensional picture of the nucleon, it is essential to perform reliable extractions of the so called Generalized Parton Distributions (GPDs) and Transverse Momentum Dependent functions (TMDs). The non-perturbative nature of these functions force us to employ models and often times make strong assumptions and approximations. In turn, this results in issues that must yet be resolved from the theoretical point of view. In this talk, I will discuss about some of these issues, in the context of TMDs, as well as some of the limitations that current data sets present in their extraction. I will briefly discuss about diquark models in the context of both GPDs and TMDs.