No, there should NOT be 2 cues.
Look again, and I don't know how to make this more clear:
Join in Progress IS NOT, a speed to the end/get to skip a boss or 2 card. It was NEVER intended to used for such purposes or intended to be a 'skip' button. It was a 'sure, I don't mind helping' button. It was actually intended to help out groups who got stuck or abandoned. Therefore, there should NOT be 2 cues. Because the reality is you should always plan on starting from the beginning of any Duty you join. That is how each dungeon was intended to be played. So no, there should not be 2 cues because the whole point of 'Join In Progress', which is to HELP others, is lost then.
And putting all the 'loot' at the end, solves nothing. Then people will spam until they see 2/3 or 3/4 ...because after all, loot is only at the end right?
At that point, if they give 2 cues, they might as well allow people to select which point they wish to start from:
Beginning:
After 1st Boss:
After 2nd Boss:
etc...
Because THAT is how the 'withdraw' players are treating it anyway...so might as well give everyone the option. This way you could even form your own party to spam the boss of your desires for faster loot, leave and do it again. That's what people want right?
Heck, lets go further...just give us the option to once a week buy a cap of myth tomes or that one drop in CT you wanted with real life gil. Because again, time is too precious to actually rely on clearing a dungeon from beginning to end...let alone farm the dungeon. Just let me buy what I want and look cool and be done with it....
/sarcasm off
If anything, they should just get rid of your right as a player to select where you get placed if using DF and randomly assign everyone to a group, regardless of whether it is in progress or starting fresh, and NOT let you see where you are (beg/middle/end) until you actually enter...sorta like how Dungeon Roulette only shows you what Duty you rolled once you enter and the CS plays. This way, by default those who are trying to 'farm for a better start' would HAVE to take the 30 minute 'abandon' penalty and this behavior would mostly stop.