This topic has been done several times before. Knowing the number of stacks does not help Veigar's enemy as much as being able to see his total AP, which is readily available already.
-Bard gains different abilities depending on how many chimes he's collected
-Nasus's Q scales directly off how many stacks he has, not so much his other stats
-Thresh is kind of a mystery for me, because he gets plain old stats from it, but anyway, it was a weird design choice for Riot. Honestly, last I checked, I didn't notice the counter, but I'll believe you and assume that it is actually there.
Also, Sion stacks health when he farms (as a lot of the community doesn't seem to notice for some reason), but I don't see anyone asking for a count of his stacks to be shown to other players.