Add the ability to rotate the map. Is very useful for mobile devices, for example in a GPS navigation app.

Maybe use hammerjs (if available) to allow the rotation of the map using two fingers on mobile devices.

OpenLayers3 supports this out of the box.

Support for WFS (Web Feature Service) layers: http://en.wikipedia.org/wiki/Web_Feature_Service

You should come up with an documentation like jQuery does, each function has a example on the page so we can get an understanding of how it is used than minimal examples on the Examples page.

Any idea when this will be added? It would make Leaflet extremely powerful.

Ability to easily control the z-index order of tile and vector layers.

It would be nice to be able to control the visibility of a marker (hide/show) at either the marker or the layer level. I currently do this in both Google Map API and Openlayer Map API to allow the user to filter between different types of markers on the map.

http://www.topix.com/map

Ability to set rotation angle for markers.

OpenLayers has functionality that allows configure zoom levels by resolution or predefined scales. It is planned similar functionality in Leaflet?

Allow the use of inline SVG for markers in stead of a img tag. This would for example enable using libraries like d3js to generate little animated pie charts shown on the map.

It would be great to have a mobile app for Windows Phone 7 and 8.

it sould be nice if we ware abble to number the markers, for a search around a point for exemple.

Add a slider control for adjusting the opacity of an overlay layer

Support for tiled GeoJSON services.

Handling dateline (180 meridian) crossing automatically, ala Google Maps. Polylines and polygons that cross the dateline are connected via the correct shortest route (e.g. polyline from Hawaii to Japan), are clamped to a max lon of 180/+180 and repeated as the map is panned through each iteration of the world.

In the class L.geoJson we have the method geometryToLayer ("Creates a layer from a given GeoJSON feature"). It would be great if some sort of inverse operation was available. That is, in the class L.Path there should be a method "layerToGeometry" which would create the essential geoJson data for the given Vector Layer (be it a Polyline/Polygon/Rectangle, a MultiPolyline/MultiPolygon, or a Circle/CircleMarker, for which the radius could be stored in the properties). The class L.Marker should have this as well.

It would be cool if one of the examples show the use of a custom projection. This could show how one could use leaflet to pan/zoom around a layer representing a simple image; or a local tile set (e.g. one city). This would also show how to create a map that doesn't wrap around the east/west.

Add a set of standard colored markers to the package.
Now there's just blue, but being able to say 'marker-icon-red' in place of 'marker-icon' would be great.
(I have made th standard marker into 11 other colors, and happy to share them)

Please add support to handle secure WMS with basic authentication.

I want the size and content of icon should be depend of zoom.

same L.TileLayer.Canvas but for icon.
I think about something like:
var canvasMarker = new L.Marker.Canvas(<op>);
canvasMarker.drawIcon = function(canvas,zoom){
var context = canvas.getContext("2d");
context....// work here
}

Google Maps JS has a gestureHandling option which can be set to 'none', 'greedy', 'cooperative' or 'auto'.

Currently, Leaflet only has a 'greedy' mode where moving with one finger pans the map.
But when Leaflet is used as part of a scrolling page, this one finger panning interferes with page scrolling.

Google Maps' solution is to require two fingers to move the map when gestureHandling is 'cooperative'.

This would make Leaflet a no-brainer to embed in scrolling pages. I couldnt find plugins that enable this behaviour.

More: https://developers.google.com/maps/documentation/javascript/interaction