Your assessment of leeching mentality is right, once a dungeon is perceived as ‘rushable’, some players will then always wait for a rusher to do the thing as a default tactic. I would say this highlights when a dungeon doesn’t hold enough intrinsic interest to the players – they only care about the boss. Examples: OT, which holds nothing except fragments of XP, with some threat a clearer could even fail (paralyse pony) =>people leech. Theatre, less so because people can at least look for the T-rooms and the paths are much more split.
Ultimately people leech when their assessment informs them that there’s nothing of value on the minions to deserve their effort. Though certainly XP can be a sweetner not to leech—cf. Parasites.
The Ice Cave rework handled this amazingly, taking a dungeon that was massively leeched, and dissolving that by making it a single trail to follow rather than a branching path, but watch your step! can’t just run blind, and hiking the XP to make it “more fool you” if you don’t bother moving. So the lazy are punished but in a non-intrusive way for the others. And rushers certainly still can rush it, but it’s pointless because of the need to kill the enemies. They also deprive themselves out of the XP.
If designer actively wants a thing to be rushable, it can be made so: undodgeable quiet/pet stasis/slow and/or walls between the rooms. As Castle has shown, where now it’s only the really weak/inexperienced who would miss the guards, unlike in old iterations, and even its event chest is v.v.rare a wing misses it. Or the right mix of enemies & effects to make rushing actually tough. Tomb had this (before pets only a really skilled player would rush) and CDepths (before so many people got Divines). Even WC the meta for the longest time was to clear since rushing failed so often, & people don’t like to fail. Unfortunately it’s intertwined with cheatclient since the pain of a death doesn’t hit them like it is designed to, and they lose the death-threat-disincentive that is so critical to Rotmg’s game balance & difficulty.
So in relation to LH: I would say if you want the rooms to be viewed as more than intermediary filler, give them some function/purpose, could be required kills to progress like Ice Cave has, or they affect the boss like Parasite does so a full clear gets an easier fight, or be some type of switch like Shatts. Alternately offer something unique, like how the golem rooms have the Trickster ST items there could be Oryx-themed items in the Oryx rooms, etc, or longlasting consumables that can’t be taken out of the instance so fighters are buffed in relation to the lazy. Or mini-vials that unlock some shortcut or other thing. Give a reason to participate that overcomes a temptation to leech and players will respond.
…though Shatts leeching pre-2nd shows that we have the community that we do, and some people will take any excuse for a lazybreak.
This is why minion HP scale has to be done wisely, since if there’s no incentive to kill them, anyone who tries is hamstrung by everyone else ignoring it.
About teleporting pros and cons, the points you make are certainly true, though they’re not to me reasons in and of themselves – if the boss is derpfailed by all TPing out, or if ppl choose to leech and miss some juicy XP, then “haha” to them, even moreso if there’s loot on the way they miss out on – and were a voicechat group to be organised enough to sort a rotation where people TP in, do a portion of the fight and then TP out, kudos to them for being so professional about it, and that’s the kinda thing that the raider-types would love organising, I guess.
I’m taking a long way to say TP is not something that’s good or bad in itself, just you get the outcome based on the design, and TP-disallow inevitably leads to the clump effect where players stay in the big group for fear of missing out. High minion HP scale also leads to clumping since it’s usually inefficient to split up groups. Both features together curtail a lot of player freedom in these dungeons compared to others and punishes hard the disorganised which is what pub runs by definition usually are.
Ah it is complicated intertwined issues after all! Sometimes they do take a lot of words to talk about. S’why it’ll really come down to designer’s vision since you could listen to 500 people who’d each have a different shopping list of things.
I suppose they have a niche vs enemies that use directed attacks, so the rogue can cloak and hit em while they’re focusing aggro on the group, unfortunately you’ll have that hurdur melee with high pet who’ll try and hero it. Like we’re seeing more of in shatters where instead of letting the rogue go and do the switch a couple of others follow in as well out of ego/impatience/whatever. Maybe if an enemy had meatshields minions that alternate vuln/invuln, and move to cover the direction of sighted enemies, but allow rogue to do dmg unhindered (is this kinda how crusade works?? I’m not the most experienced, never been in LH on a rogue in actual fact. 
).
