Many times, we had to implement workarounds to compensate a feature that isn't available in Kendo (User voice is full of those missing features).  Sometime, a small change in Kendo's source code may be a solution to complex workaround.

Knowing that Kendo UI has been build over many open source libraries, it would be nice to use the same spirit by allowing users to contribute to Kendo if they want to do so.  Users could help adding features to existing widgets but they could also help to improve the documentation or by creating demos.

You'll still have to review the submitted code to make sure it meets Kendo's standards but I'm sure Kendo and the users would both get the benefits of those contribution.