How to send A/B testing fields in click stream events

I have a lot of production clickstream events and would like to do A/B testing on some of the features. Right now I sent each feature value in a separate column in my click stream events which I think is not right as the features for A/B testing are very volatile and continue to evolve\change\add. This leads to change in my schema and change in my tables which are created for click stream events

Is there a better way of doing this?