Yeah it's been a while since i've been to the RES, but I still prefer it to Ekka. I had the opportunity to visit Ekka before they developed the old showbag hall into event space and erected the permanent temporary monstrosity - so i've seen both of its two most recent incarnations.
As for my opinion on how the grounds stand today, they are a shell of what they once were. The entire precinct is choked by the railway bifurcation, funnelling everyone through two relatively narrow thoroughfares. Between this and the land sell-offs, areas are fragmented - splitting similar areas of interest off from each other and moving them to other places to accommodate them. It becomes even harder to navigate closer to the evening when EkkaNites starts as the vomatorium for the arena feeds into one of two major routes to get around the grounds, choking that passage, with little alternative.
The grounds on a whole are hilly, and to get around to see everything you're essentially hill climbing all day long.
The 'public transport' accessibility to the Ekka relies primarily on the Exhibition loop line, meaning that although it is capable of moving large amounts of people out of the precinct, it dumps them at a metropolitan station that is busy enough without exhibition traffic, requiring an interchange - so that just makes it worse.
Unfortunately the earliest images for the RNA grounds on Nearmap are October 2009, and although some development had already occurred, you can see the land selloff continued throughout the past decade:
October 2009 (oldest image)
August 2012 (during Ekka)
August 2018 (during Ekka)
March 2021 (most recent)