I have to say I am quite happy with these changes. My guild may actually benefit as those players who do not complete due to the current 80% cut-off can maybe add more to the reward (not to mention that annoying situation of being 5 mins from finishing and someone else completes the gq first). We already do gq daily, so no issues there. We also don't keep inactives in guild.
That being said, other guilds may be more relaxed about gq's, but i don't see that as an issue either. Those guilds that don't care, can still ignore gq, maybe do the odd one and not get stuck for days, as the gq will change daily. Those guilds that fill up on inactives simply to gain the higher guild coin rewards, well, they will have to decide whether to continue, or clear them out. I do think this will help reduce the number of guilds filled with non-playing players.