Yes, weighing by coins × lockup period would be different, and possibly better, than weighing by a single-point-in-time snapshot.
Or perhaps backward-looking coins × holding period, which doesn’t as accurately capture future skin-in-the-game, but is still an indication of ZODLing and mitigates lend-to-vote.
However, there are difficult questions on defining/implementing such lockups, since people need to move money around between their own wallets and across pools in network upgrades. See, e.g., these questions. I would love to figure out how we want to define the desired lockup/holding period, and then find a privacy-preserving way to implement that.
I do think that staking a lot of my personal wealth behind a decision should indicate how strong my personal convictions are, and that’s worth something
One problem with this argument is that “a lot of my personal wealth” is relative. Does a rich millionaire, who used 1% of their net worth to buy $100k of ZEC because YOLO, have x10 the personal conviction (and thus weight) compared to a brilliant young ZODLer with student loans and a mortgage who holds on to $10k of ZEC? [1]
I would much rather hear what they have to say, here or on zecpages, than try to guess the derivative of their utility curve as a function of their ZEC holdings and price.
[1] By no means implying the latter is a good idea. Holding volatile assets while in debt is leveraged speculation, and will probably wreck you — if not this time around, then by setting you up with a really bad habit.