I agree with you the e-tickets do not yet work well for RTWs: too many different, not-very-compatible, systems in play.
That said, the rules seem very clear that you can change flights/dates without charge, whether an e-ticket or paper ticket. Rule 16.A of the fare rule says this about changes after ticketing:
2. After departure.
...
a) No changes permitted on remaining outbound sectors up to and including first international sector
b) For all other sectors rebooking/revalidation permitted at no charge, also in case of E-Ticket for all other sectors
changes to carriers / flights / dates permitted at no charge..
I think the problem may be with the term "re-issue." The *RTW rules use the term re-issue to mean any change that requires a change in itinerary. But most airlines (incl. UA) also use the term re-issue to mean revalidating an e-ticket for a changed date/flight, but no changed itinerary. On a RTW, there is no fee for the latter type of "re-issue," but many travel agents and airline personnel don't seem to fully understand the distinction.