The reason why there is a "need" to avoid interpretation issues is because you don't have a standardized ballot produced by non-partisan experts. These problems simply do not exist anywhere else in the world - what is it about Americans that makes them so uniquely unsuited to marking an X in a box beside a name? Oh wait, this is why...
Let's compare and contrast.
As for being a republic, I'm not certain how that is related to the issues at hand. Indeed, making elections a state-run thing is one of the most grotesquely stupid decisions ever made by the Founding Fathers. Secure, fair and free democratic elections ought to be handled at the federal level. This is indeed how other Republics do it, so not really sure what you're trying to say.
Blockchain voting is currently being developed by multiple organizations. It'll take time but eventually I think there will be a solid case for switching to those systems.