Personally I prefer time gates to RNG.
With time gates I can decide whether or not I want to bother hitting my cap for the week/day/whatever whereas with RNG my progress may be hindered by bad luck.

The only time based gates that really bother me are the ones for gathering nodes. I found them tolerable in ARR since they were only for max level crafting items for the most part. I hate that Heavensward has incorporated materials from time based nodes into leveling crafts.