No, you didn't overlook information, you just made an erroneous assumption. We actually have about a dozen warlocks and multiclass warlocks in our campaign but only 2 multi-class wizards. In fact, the cleric with Plane Shift is the only high level single-classed caster. Understandng other people's perspectives, makes for a more collaborative campaign. Just because my players don't play the game the same way that you and your players do doesn't mean they're playing it wrong.
Point to me where I said you were playing the game wrong? Seriously dude, stop martyring yourself for a moment and listen. You presented me with the information that your group had a cleric who could cast 7th level spells, and a wizard who maxed at 5th. That, on the face of it, doesn't make sense because Clerics and Wizards have the same spell progression. If you played the game the exact same way I did, that wouldn't make sense. So, I assumed you played the game in a different way. You mentioned you were in Greyhawk, so perhaps you liked an older style of game. Players and DMs on this forum, who play differently than I do, have parties with varying class levels, because they like that style of game, and it seems more prominent among older gamers.
So, the thing I did wrong here, according to you, is assume that you didn't play the game the same way I did, and dare, DARE suggest that perhaps your group being non-standard is the reason you are using Plane Shift in the way you are.
Now, if you want to continue scourging yourself over the audacity I had to assume your group might be unique, and have a unique perspective, go ahead, I can't stop you. But if you think I'm going to somehow recant my assumption which was based on incomplete information, then don't hold your breath.
Dungeons and Dragons took its inspiration from fairy stories, fables, religious tales, science fiction, and classic horror stories/movies. Plane Shift wasn't added to the game for a specific mechanical purpose, it was introduced because it had literary pedigree. You may not see any mechanical need for it, but that pedigree remains for a lot of us. Watch a movie like Constantine and you can see how Plane Shifting can serve an interesting story. Teleporting is much more vanilla.
What are you even going on about? Do you know what the literary pedigree of Plane Shift is? Shifting... to another plane of existence. You said your group was using it to transport to another plane for the sole purpose of camping and then fast traveling to another location on the material plane. Those are different things. I don't care if teleport is "vanilla" it does that specific job better, because it is designed as a fast travel spell, where as Plane Shift is designed as a spell to allow travel to other planes of existence for the purpose of adventuring in those planes.
And yeah, I don't see a mechanical need for the spell, because the spell is a story-telling conceit. And, in fact, it can make for BETTER stories if instead of being able to declare "We Plane Shift to the Ice Queen's Manor" they have to find a portal, and then travel through the other plane of existence to reach the Ice Queen's Manor. There is no mechanical need for it, because if the story needs us to travel to a different plane of existence, there are much cooler and more nuanced ways to accomplish it even if we don't have the spell.
And, if you want to fast travel as a druid, you really shouldn't be ignoring Wind Walk, which as I said is a 6th level spell that could allow you to in the same two days you are using for Plane Shift to travel 1,200 miles in essentially complete safety. That is a MASSIVE distance, since it would normally take a group 50 days to travel that distance.
Please explain the trick for utilising Phantom Steed! It feels rubblish now and I miss it. The spell lasts an hour and states "For the duration, you OR a creature you choose can ride the steed." So the mounts can only take one rider. If trying to create mounts for the group, for 4 people, you would spend 40 minutes casting rituals for 20 minutes of riding. That doesn't sound viable at all. For 8 hours travel using spell slots, you would need a whopping 32 spells. Any advice is welcome!
Well, first of all, I don't remember the line about limiting it to a single creature. So, if you rule that only one creature can be on the horse at a time, no matter what, then things are going to be different. But, there is also no reason to assume that you can't carry a creature while riding the horse. That can cut you down to two horses. Of course, you could also make the argument that since the horse specifically has bits and bridles and all that, that they can be hitched to a wagon and pull it, taking you down to one horse
Sure, if you strictly read the spell and only allow a creature and only allow a single creature on the horse, those don't work, but you don't even really need that. You said it only allows 20 minutes of riding, but that's false. Because nothing says you have to wait until all four horses are summoned. You are moving at 100 to 200 ft per round, that is massively fast. Nothing is going to be running you down, and you don't have to go the full distance you can find a safe spot, the party will filter in behind you.
Sure, you can make this a terrible danger that no sane party would try, ect ect ect, but it isn't like you have to follow roads, so the chances of ambushes or anything else are pretty limited.