I feel that Escape was a decent continuation except for some glaringly stupid portions (Monkey Combat). I really don't believe GRIME was the worst thing about the game or the progression. I mean after all, Grim Fandango, easily one of the best adventure games ever created, was built using GRIME, so you can't blame the overall game on the engine alone. I imagine part of the problem with Escape in GRIME is partly due to the limitations that they were put under being required to build the game for multiple platforms (Playstation 2).
I chalk Escape's comparatively lackluster appeal more to changes in writing staff over the years, catering to the lowest common denominator in terms of platforms, and a general lack of story direction.