The current withdraw penalty is too harsh and it negatively effects partial groups a lot and users who are not trying to do anything bad get punished.
A lot of times parties that don't have a full 8 or 4 are punished because 1 guy is afk and you didn't know. Or someone hits cancel because they were checking their retainer. Got a 30 min cool down because the party lead queued and one guy withdrew because he was getting something from his retainer, the PT lead queued again and the same guy withdrew again because he still wasn't ready. 3rd time everyone clicked but one guy who apparently left for a bathroom brake and didn't say anything because he thought he had time because of the retainer guy. Needless to say everyone got locked out for 30 min and the group disbanded.
This also makes it so you can't go the bathroom or leave the room without the fear you will be penalized. Before I would go do other stuff if it was taking awhile like use the bathroom or get a drink and now I can't without risk of penalty.
Lets look at what causes the problem they are trying to fix. 1 person withdrawing a bunch of times. This is usually caused by a tank or healer trying fish for a run in progress for dungeons or crystal tower.
Now SE realized the reason people were doing this when crystal tower first came out the duty finder would tell you if you were going in to a in progress run and put like X/4 telling you how many bosses were killed. Later they changed it to always say 0/1 for all in progress runs. However this did little to stop people from withdrawing a bunch because even though the game told you 0/1 in progress it was still telling you that you were getting an in progress run and possibly closer to the last boss where you get the best drops and limited tomes. Also SE never changed the way dungeons in progress worked they still gave you 1/3, 2/3 ect bosses killed making people who wanted fish for runs cap myth or soldiery faster constantly fish for runs.
The very simple fix for this problem is to not show at all if you are getting a in progression run at all for all raids and dungeons.
I have played wow some and they had the same problem when with their dungeon and raid finder, it would tell you if a run was in progress and how many bosses were killed. People (tanks+healers) kept withdrawing resetting the queue a bunch in hopes of getting a run on the last boss so they could get their Valor points which are very similar to the limited tomestone in FFXIV. When Blizzard took out the indicator that showed if a run was in progress all the withdrawing nonsense pretty much stopped except for the very rare occasion which usually was because someone was afk or not ready. However constant withdraws were gone.
So SE its a lot better just to take away the in progress indicator which will fix the problem then to punish players who may not of been ready or if someone in your group was afk. Having a 30 min lockout cause your party mates were checking their retainer and hit withdraw isn't fun.