Fine-Grained Karma Voting

A friend on the forum the other day wanted to down-vote a comment, which he sightly disapproved of, but even his weak down-vote voted the comment into negative karma (strong up/down votes are where users with high karma can choose to vote something up or down by multiple karma points, with strength of vote proportional to how much karma the up/down-voting user has themselves earned. But for some users, even their normal “weak” votes are worth multiple votes.) He was torn about whether he should down-vote or not. This seems to me problematic but easily fixable.

What if users who have earned the ability to up/down-vote multiple karma points could click and hold the karma up/down-vote button and then select the exact amount of karma they want to add or subtract, up to their limit? I am calling this fine-grained karma voting.

It seems to me this granularity would add valuable information of exactly how valuable an experienced forum user feels a post or comment is, and the extra work of users having to think a little more carefully about their votes wouldn’t add too much cost, at least not proportional to the benefits of the extra information.

Would love to hear other’s thoughts on fine-grained karma voting, I do not have the programming knowledge to know how technically easy or difficult this is, and I am curious if there are other costs or benefits I have not thought of?