Leslie Benzies was the former producer and designer of all past Rockstar's games. He was in the company for more than 20 years. He's responsable for 50% of all the masterpieces we like. From GTA SA to GTA V and through Red Read Redemption, this guy was along with Houser brothers the spirit of Rockstar Games. Actually, RDR was a mess and this guy maintained control of the situation and managed to pull out the game while the Houser brothers were freaking out.
In 2014 he took a sabbatical year of Rockstar and in 2016 he left the company, and then started a lawsuit over royatly payments. He was the main leader in GTA V's DLCs, and that's a fact because we even have audio files from datamining some years ago in GTA V Story Mode.
Not taking any sides, because I like Leslie same I like the Houser brothers, but this guy was one of the three pilars of Rockstar, and when he left, the company became a mess. Houser brothers are trying to fix it, and probably they will, but while they figure out what to do with one of the main leaders out, the future of GTA V became a wreck and they focussed on online to not be silent for years. Bad thing, for Take-Two saw a great proffit on it and now what was a counter meassure has become the main thing in the company.
I do hope Houser brothers do not lose sight for the Story Modes in the future, tho. But being honest, Rockstar Game's future right now is a mistery. Only RDR 2 and the next GTA will tell how the company now manage things.
TL;DR Leslie was one of the main leaders and when he left Rockstar Games became a bit of a mess. But they're trying to fix it.