It's impossible if you take “every issue” literally, as you are multiplying the number of pdecisions that must be made by each participant per unit of time so much that the time to consider them is non-existent.

It's less impossible if you reduce it to the kind of decisions typically made by a legislature, which mainly just sets rules for executive and judicial officials to apply in deciding more specific issues.

But even then it's of dubious practicality; obviously not every citizen can have a full-time legislative staff, and most of other things besides legislation to devote their time to.