I guess that really depends on how you view honor. I don't honor every game. If for example my bot lane feeds 8 kills in 15 minutes, says gg and then just starts inting. I probably won't honor someone that game unless one of the other lanes does something I find really impressive (A super cool baron/dragon/herald steal for example, or just earnestly struggling to try and carry a 3 vs 7).
If my bot lane feeds 3-4 kills early game and manage to crawl back up I might honor one of those players if I feel they made up for their early game mistakes. (Simply not deciding to int after goofing isn't a reason for me to honor them though).
Saying that you don't always get to see the impact of other players isn't really a good argument IMO as you should be watching the map regardless of what you are doing. You MIGHT not see anything happen but if you aren't like AFK farming top or something you should have an idea of who is doing what.
Again referring to the honor credentials the descriptions are Tilt-proof (The not inting above is a good example), Leadership (Shot calling is something I always try to do when I can get ahead early game, even more so if I am behind and I think an ally is making a bad call), and GG <3 (You enjoyed playing with them) this one is the least applicable to your argument because if you didn't notice them they were more of a neutral party than a fun player.
The idea behind honor, and I don't remember if someone from riot said this at some point or not, is to honor someone you had fun with. Not because they carried you, or happened to get a lot of kills. Anyway I believe that the reason they don't let you see information is that they don't want people making votes based on KDA, and I am of the opinion that if you need to see their KDA to vote for someone at all, then no one made a good enough impact for you to vote in the first place.