the layouts are definitely limited for this control compared to other established diagram controls:
http://demos.telerik.com/aspnet-ajax/diagram/examples/overview/defaultcs.aspx

looking for a swim lane layout, something like this:
http://gojs.net/latest/samples/swimlanes.html

The connection lines should not intersect with one another(would depend on the layout obviously) and be smart like visio.  The current layout choices are very messy when rendering data that has lots of connections in and out of shapes.

As stated by another developer in this forum, the StartCap and EndCap settings do not work at all, I have tried everything, the connections never have the filled circle and arrow.  In fact if you set them, they make the control very unstable in the browser.

Feel free to reach out to me as I have evaluated the control for use in our infrastructure and its just not mature enough yet.  Any idea when the next big release for this control will be?

Thanks,
dfabri@arrayworks.com

The text within the shapes should be wrapped automatically.

A connector that is only connected to one shape cannot be imported via JSON.
Tested here:
http://demos.telerik.com/aspnet-ajax/diagram/examples/saveload/defaultcs.aspx

JSON:
{
    "shapes": [{
        "id": "nadal_winner",
        "background": "#f18100",
        "hover": {
            "opacity": 0.2
        },
        "cursor": "pointer",
        "content": {
            "align": "center middle",
            "text": "R. Nadal",
            "color": "#fff"
        },
        "selectable": true,
        "serializable": true,
        "enable": true,
        "type": "rectangle",
        "path": "",
        "visual": null,
        "x": 180,
        "y": 155,
        "minWidth": 20,
        "minHeight": 20,
        "width": 140,
        "height": 30,
        "connectors": [{
            "name": "Top",
            "description": "Top Connector"
        }, {
            "name": "Right",
            "description": "Right Connector"
        }, {
            "name": "Bottom",
            "description": "Bottom Connector"
        }, {
            "name": "Left",
            "Description": "Left Connector"
        }, {
            "name": "Auto",
            "Description": "Auto Connector"
        }],
        "rotation": {
            "angle": 0
        },
        "stroke": {
            "width": 0,
            "color": "#fff"
        },
        "connectorDefaults": {
            "background": "#444444",
            "stroke": {
                "color": "white"
            },
            "hover": {
                "background": "white",
                "stroke": {
                    "color": "#444444"
                }
            }
        },
        "undoable": false
    }],
    "connections": [{
        "from": {
            "shapeId": "nadal_winner",
            "connector": "Right"
        },
        "to": "OK6oDroWug",
        "id": "OK6oDroWug",
        "background": "Green",
        "hover": {
            "stroke": {}
        },
        "cursor": "pointer",
        "content": {
            "align": "center middle",
            "text": "",
            "color": "#444444"
        },
        "selectable": true,
        "serializable": true,
        "enable": true,
        "startCap": "none",
        "endCap": "none",
        "points": [],
        "stroke": {
            "width": 2,
            "color": "#6c6c6c"
        },
        "select": {
            "handles": {
                "width": 8,
                "height": 8,
                "background": "white",
                "stroke": {
                    "color": "#444444"
                }
            }
        }
    }]
}

It will be possible to detect when a new diagram connection is created or modified.

It will be possible to disable the various actions that the diagram control currently supports. You can find them listed in the following help article: http://www.telerik.com/help/aspnet-ajax/diagram-rich-layout-interaction.html

Does not matter what value is set to the Connection's StartCap/EndCap properties, the ends of the connection are rendered as if the value of these properties is "None".