Reactions and action modifiers timing

Bloodartist wrote:

Note that I have always been against using phrases such as "before X" or "after X" in cardtext. Things should happen at exact moment X and not before or after which is vague.

"before" and "after" are defining that exact moment. They are not vague as they indicate the exact moment compared to X.

There are three cases:
1) two effects should happen at the same time, in which case you have to order them
2) effect A should happen before effect B
3) effect A should happen after effect B

Case 1) the effects Vessel and Anarch Revolt have the same timing window "during your unlock phase". So you can order them.

Case 2) When a minion is blocked, there is normally a combat. But some cards have effects that happen before (for instance, Change of Target or Power of One)

Case 3) and some cards have effects that happen after (Cats' Guidance).

In cases 2 and 3, "when X is blocked" would be ambiguous because you wouldn't know if the effects happens before or after. So your "exact moment X" is defined using before/after.