Zoran Primorac vs Oh Sang Eun | 2006 World Table Tennis Championships (MT QF) 

The arm blocking issue is blown out of proportion.Even in the 90's Primorac won more points with his backhand serve than the blocked pendulum serve. The hand blocking works if you don't telegraph the spin with your shoulder and elbow movements otherwise everyone would score 5 unreturned serves in a row like Liu Guoliang which was not the case for 99 percent of TT players. Anyway,the hand was held way too high I don't think it really blocked the blade action.Oh Sang Eun didn't seem troubled by Primorac's serves.

what you see on broadcast is a completely different angle than what the opposing player sees