That's not what people talk about. The problem is not the realism of the moving part but their interest. Too many people use RPG Maker for what is in fact more an extended visual novel than anything else.
Take the classical case of the MC being able to move around the world :
With Renpy, you click on the door of his room, and now have the choice to click on the doors in the hallway or to click on the stairway. You chose the last option, then click on the main door of the house. Now the MC is outside, and you are looking at a map of the world. One more click, and the MC is now in a coffee shop. In 10 seconds and 4 click you moved him to another part of the town.
With RPG Maker you will have to move the MC case by case, then remember the path to the coffee shop while still moving case by case to it. Many click (when it's a version of RPG Maker which support the mouse) and at least one full minute to do this. For what ? What it add to the game to do this ? Nothing at all.
When it's a real RPG or at least a RPG-like game, alright, there's no problem. You have the choice of your next destination and you move to it. But people like icestor, iccreation or daniel k, that you named as "best RPGM developers", mostly don't do RPG-like. When you move, you have one and only one possible destination...
In the end, in their games, you pass more time moving to the next scene, than looking at the said scene. They are not bad story writers, not bad CG makers, but it's far to make them "best RPGM developers" ; their use of the engine make them more in the worse part than the best.
Anyway, if you don't do as they expected, most of the time you crash the game. Just because (at this time at least) they never thought outside of their box. "The player must go here, must do this", that's all they took in count. And when the player don't do this, don't go here, it become a whole no man's land where everything can happen ; and half of the time it happen and end badly.
There's a whole world between their best games in RPG maker and the average Asian game made with it. The last ones have less mini-games, more need to move from a part of the map to another, but at least you've a reason to move. The map isn't a big thing with only "one possible destination at this time". You can go where you want in the order you want and so write your own story in the game.
That's the purpose of RPG Maker and how a game with RPG Maker should be done. If you want a more directive game, or even a full visual novel one, you use an engine designed for Visual Novel ; whatever it's Ren'py, Tyrano Script or another one. But you don't use RPG Maker and force the player to pass half the game walking from a given point to another given point.
Too this, you also need to add the fact that Ren'py is optimized for picture display, while RPG Maker is really slow when it come to display picture which cover the full game window. With 5 years old computers, it can take few seconds to RPG Maker to display one single picture, when Ren'py do it instantly.
