One of the major problems is that people like Namko (who I don't doubt means well and is honestly trying to help) simply do not understand the issue and incorrectly think they aren't affected by it. *Every* player, on *Every* NA/EU server, on *Every* ISP with *Every* possible PC setup is affected by this issue.
Here's the simple test: start casting a spell/ability, then move your character before its done casting, with 10-30 (100-300ms) left on the cast bar. Do this several times in a row. The spells will nearly always complete. If anyone can upload a video showing them successfully canceling spell/ability casts near the end, several times in a row, I'll be happy to buy you a 3-month sub. This goes for Namko, or any other player who doesn't understand this issue and mistakenly thinks it is about ping speed, packet loss, or anything else but SE's terrible, terrible servers.