More exp would be gained by leveling in normal caves, so not really a problem here.
I do like the endless tower idea
What's the purpose of going to the easy/medium map if you're always alone, there are no item drops and exp is lower than in caves? Cash drops?
I'd rather it be something like old Euro 2 casino, with rooms full of monsters that drop their normal drops and every now and again you get a mass dropper/sub/whatever.
It should be there for either exp, gold or drops. If it excels at providing neither of those then what's the point of implementing it?
Barring that (if you really don't want it dropping anything or providing stellar exp) I have a suggestion:
Have it be rooms the size of the lottery ones filled with mobs, you teleport to the next room 5 seconds after you clear a room. The mobs there drop pots (at a rate.. say a bit lower than PB? Maybe PT-esque rate?) and the actual stuff people go there for: LotteryTickets. These can be exchanged in bundles of 10/50/100/200/500/1000 for one of various (differently priced) chests that have a
chance of containing a 1M XP soulbound stone or 1M Gold or 2 Platinum Ores p12+, etc.
That way you go in, you sink money into pots/repairs/consumables (we know how Sam loves gold sinks :P), you get decent EXP (but less than if you were EXPing) and, say, get 1000 Tickets. You then trade them for 5 PlatOre chests (priced at 200 tickets each) and get 2 plat ores total from the 5 chests (along with 8 puri 10< plat ores). There's an element of randomness, an element of luck, but grind in there long enough and you are virtually guaranteed to get whichever chest reward you want (if the rates from chests are decent, say 1/5 or 1/10, depending on ticket price). If you trade all the tickets you get for EXP chests you'll eventually reach a point where the exp from the mobs + the exp from the chests is about 5-10% higher than leveling in a leveling cave solo. If you use them for Ores, you get a few ores for 5-6 hours of grinding there and decent-ish exp. If you use it for gold we finally have a way of adding gold to the economy that's more fun than farming ST/BC.
Also mob variety would help to keep it "fresh", e.g. first room can be either Ghouls or ZumaArchers or WedgeMoths or Wolves (randomly generated, but all have the same stats).
What do you all think?
Also Mir has allowed instances since lottery was introduced/first private servers came with pet leveling rooms filled with scarecrows :P
Edit: Ignore the first few paragraphs, I only now registered reading the rewards bit at the end of your OP. Also works with my idea with the tickets.
E.g. if you stop at room 40 you get 300 Tickets, if you stop at 50 you get 400, if you stop at 80 you get 1000. You can stop at any time, but only gain large ticket increments (100-200) if you stop at a room number divisible by 10 (so room 40 you'd get 300 tickets; room 45 you'd get 310 tickets; room 49 you'd get 320 tickets; room 50 you'd get 400 tickets). It's incentive for people to not just stop whenever and cash out, but to grind there just a bit longer.
You could also "save and quit" at any time, but it sets you back by 5 or 10 rooms or by a fixed percentage of the room number you're in (10-20%?). So if you take a break at room 43, np, but you start in room 36 (43 - 15%) when you come back. If you take a break at room 78 due to RL stuff.. well, tough, you go all the way back to room 66. Or you cash out at 78 and only get 825 tickets, 25 more than at 70, and 175 less than you would have gotten if you'd done 2 more rooms.
