Sthenno came over today for one of our "shout numbers at each other" visits. We talked a lot about Diablo 3 and how scaling will work in the game. He is strongly of the opinion that having an achievable level cap is really poor design and I am inclined to agree with him. Even given that we will get all of our skills and runes by level 60 I think there are some really good arguments for letting players level beyond that. The only things players gain from levels in D3 are the ability to wear better gear, skills, runes, and stat points. The stat point gains are pretty important at low levels but at high levels when we can expect to have stats in the 5,000 range (see next paragraph) so getting an additional 7 stat points from a level is pretty much irrelevant. Certainly a brutal ramp up in XP cost to level would be appropriate; simply increasing the XP required to level up by 50% for every new level would allow really hardcore players to get into the late 60s and the most extreme lunatics could keep going into the low 70s but their advantages would still only be in the 1-2% range. It would let people have fun gaining XP forever and have leaderboards for level but avoid any significant power inflation.
The other thing we talked about was how high stats are going to get. Right now each class has a stat that gives them bonus damage. The Witch Doctor, for example, gets % bonus damage equal to Int. That is, if the WD has 100 Int they do 100% more damage. There is a WD skill called Soul Harvest that grants 750 Int and heals for 20,760 on a 15 second cooldown when you are level 60 - unless they intend that this skill makes the WD by far the most powerful class we will need to have an Int score of ~5,000 at max level. If we expect to receive 20,760 in healing every 15 seconds we must also assume we have a health pool of at least 50,000 which requires 5,000 Vitality. Clearly my estimates are based on my gut feelings of what is 'appropriate' but either way I think we can be pretty sure our stats will sit somewhere between 3,000-10,000. This has some fun consequences.
The biggest consequence I see is that other stats will also end up being this big as they scale in the same fashion. Magic Find is the big one here - it seems clear that every character will be able to rock 1,000% MF without even trying and presumably people who really go for it will be able to have 5,000% MF or more. If MF scales linearly then people would be getting 50 times as many magic items as 'normal'... which boggles the mind. Given that MF scaled logarithmically (ish) in D2 and that getting 50 times as many items is ridiculous I am pretty sure we will see the same mechanic in D3. Perhaps the first 100% works at full capacity, the second 100% works at half capacity, then 20%, 10%, etc. Regardless of how the curve off works mathematically it is clear that after hitting 1,000% MF there will be virtually nothing to be gained by stacking more.
While it seems a little bit bizarre to have a system where absolutely everybody has enough MF that stacking more is completely useless it neatly solves a few problems. First off it means that people won't really have to make significant sacrifices for MF on gear. As long as you pick a bit of the low hanging fruit and get a little MF in the easiest ways possible you will have plenty. Also this means that the furor over MF being shared amongst group members is completely irrelevant. Everyone will have 1,000 MF anyway so if you are crazy and stack 5,000 MF for some reason you still lose practically nothing by giving it away! Essentially this means that MF is a pretty meaningless stat as long as everyone gets the little bit that they need. This reduces gearing to a performance based weighting and means that those with optimal MF gear won't really be able to get significantly more drops than everybody else - the best way to get gear is to play well and kill efficiently.