I just got my first 20 Killstreak in about... 8-10 months? And then it hit me, why not make the community I'm closest to share their 20 killstreaks! That was my latest one. Put your 20 killers in a reply! (P.S - I was wrecking GetriedeWasser a.k.a the #1 person on the leaderboard, but she left. This was the same match as that 20 killstreak above.)
I don't have any pictures of 20 killstreaks as of now, but I have gotten them before. My most recent one was about 2 months ago in a 4 player match. I have come close sometimes, one game resulting in a 14 killstreak before dying, and then finishing off with a 6 killstreak for 20-1. Another game resulted in a 17 killstreak, dying twice, getting 2 more kills, dying again, and getting the final kill for a 20-3 finish.
Unfortunately I haven't had a 20-streak yet, I die at least once every game. >.> My best was 20/1. Don't judge me, I only played 26 games on this server yet.
Because it gives you an advantage to blockhit, when you shouldn't be blockhitting (at least minimal/not very well) on normal 1.8.
I only block hit sometimes, like 25% of the time (because I'm a really focused PvPer). Plus, I only use the animation for look purposes. And personally, I don't think its as much as an advantage as your saying, because I think the looks only slightly help.