RANDOM MAP EVENTS (NOT JUST BATTLES)

It could depend on what the map looks like. If the map is slightly more abstract then random events could easily be random and not visible.

If it is a slightly less abstract map but still pretty abstract you could have the events represented by question marks. Since not all events are hostile it would be up to the player whether he wants to take the chance of an event or not. (similar to drawing a random event card).

But if this is an in-town map with NPCs and other stuff it does become harder. You could have it trigger on certain squares. Say if the player moves through a certain corridor you could have a %-chance of an event triggering. You could also divide the map into areas and define the random event when the player enters the area. Then as long as the player is in the area the event runs. (so if there's a special merchant then he's in the map or if there's a city guard he won't let you leave without seeing the city pass)

Map events should be definitely visible. We're used to monsters appearing out of nowhere, but if a npc starts an event out of the blue it's just a wtf. Also, like you said, maps look too empty and devoid of life.

By "invisible", you mean that when you step on a certain tile, an event starts where they walk in from offscreen and do their action? It makes sense. Chrono Trigger for example did battles this way - most were visible and avoidable, but about a third of the battles in the game started when you stepped on certain tiles that gave no indication they would start a battle. Usually they were "unavoidable" tiles, like as you passed through a door or walked down a narrow passage. There's no reason non-combat events couldn't work the same way.

What part are you not 100% satisfied about?

Why not have it so that the side events like the pick pocketer etc are invisible but once you touch that invisble event, erase thae screen for a sec then have it appear with that event character visble? your still having the said event invisible but once you touch it the npc becomes visible, making it not so weird that your talking to thin air. unless you already have that in mind. just a suggestion though...

Egyptians, he never implied you would be talking to thin air, just that invisible step tiles would start the event. Like I said, I assume stepping on an event tile causes an NPC to walk in from offscreen and begin interacting with you, just like invisible battle tiles in Chrono Trigger.

Fhizban. If you can be specific about exactly what aspect of the idea doesn't feel right, I would be a lot more likely to offer possible solutions or alternatives that address it. With no explanation about what the problem is, I can't really help.