Some of the things you mentioned are like this due to legacy browsers and accessibility e.g. only links can be "active" or hovered. However, your suggestions do make a point, especially in a browser landscape that is dominated by standard compliant browsers.
As for the things you want to achieve, they are more or less doable, by using a lesser known property of the RadMenuItem -- OuterCssClass, which puts a class name on containing LI element -- and some JS.
Let me know if you need help with that.
On a side note, I have awarded you some Telerik points for the suggestion.
the Telerik team
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