Enabling accurate morphological and photometric analysis across a wide Field of View (FoV) is one of the keyscience requirement for multi-conjugate adaptive optics systems. With this motivation we present a study aimedat the investigation of the performance of Global-MCAO (GMCAO). Such an innovative concept, based onnatural guide stars in a wide technical FoV, addresses the need for an increase of the sky coverage, which is akey ingredient for future MCAO-based VLT instruments and for the forthcoming E-ELT. Using a tomographicsimulation tool, we compute a map of the Strehl Ratio in a 250′′ × 250′′ area, matching the Chandra Deep FieldSouth survey. Mock images of star and galactic fields are then built using such a map and analyzed as if theywere real and observed with the E-ELT instrumentation. We perform the source detection and two-dimensionallight-profile modeling using the IRAF/ELLIPSE code and we then compare the recovered parameters with theintrinsic data. The good match of our results claims that GMCAO is a reliable approach that can rebuild theAO concepts and can provide a frame of reference for a number of science cases.