Yeeaah, making voting rights be reliant on anything that's particularly manipulatable (e.g. everything except stuff like over an age line) is basically asking for trouble. Conceptually it might be good in a sort of ideal world, but practically you're ceding disproportionate amounts of power to whoever can figure out how to leverage the requirement in their favor. US actually has a pretty blatantly obvious one; we allow disenfranchisement for criminal record, and in part (though only in part, mind) because of that there's a number of crimes not nearly of a magnitude or impact to warrant that, that are on the books, fairly well enforced, and often enough tailored to disproportionately hit specific demographics in one manner or another.
If you had, say, military service be it, you can pretty much guarantee that there's going to be an odd trend in who's taking the most casualties, or exactly how the instruction is handled, or cultural/legal/etc. rules tailored subtly and not to drum folks with undesired political likelihoods out of the military and subsequently out of political power, or etc., so forth, so on. Some kind of means test? Language structure that favors a particular culture or demographic, specific subjects likely to be fairly unfamiliar for certain sorts, and suchlike. Basically just kind of a mess.
... that said, I could see some degree of limitation based on stake holder significance. Stateside we already do that, with specific districts voting for their own representatives, local/county ordinances, etc. It's something you should keep a careful eye on, because if there's anything locals are terrible at it's identifying when shit they're doing isn't as local as they think, but it's a useful tool for keeping on top of ground level nuance.