I agree that the altered Sarlacc in the SE wasn’t all that intimidating, definitely more laughable with it’s obvious CGI beak.
For me though the original Sarlacc always did the trick just fine in seeing that gaping maw with backwards facing teeth that acted as barbs and tendrils trying to grab hold of anything that happened to tumble in. Though it was never the look of the beast that invoked fear and dread, it was the thought of accidentally walking over the edge of the pit (or worse, being directly thrown into the gaping maw by Jabba’s henchmen) and falling down the steep and unstable sides, sand giving way as you helplessly try to scramble from some kind of hold and slip literally into the dark stomach of a beast to eventually die as it begins digesting your body.
It was the thought of that ending as you looked into the bottom of the pit that was always more frightening that the little bit of the actual beast you get to see and the massive burp it makes as it swallows you whole. Much like how a black hole isn’t fearful to look at but the thought of the fate that awaited you if you fell into it was. The SE alterations definitely took away from this effect, almost becoming comical. In the case of the Sarlacc, less was always more.
Looking into some of the additional lore makes it even more of a undesirable end, apparently it would introduce neurotoxins into your body that would immobilise you while keeping you conscious and in constant pain. It’s even noted that some believe it absorbs it’s victim’s consciousness and is how it can inflict torment for millennia, much like C3PO alludes to in ROTJ.