This is my first post in the game, though a long time player and form reader. Some of what is posted my appear in other posts already, if so that's OK. I felt I needed to say it here in order to tie everything together.
To address this issue in D3, we have to look at certain aspects of D2 and see why those aspects aided in the games overall longevity.
Progression, itemization and things to do.
While progression in both D2 and D3 is a linear process, there was much more decision making while leveling up in D2.
Not having to roll your characters and put points into stats and skills negates any reason to build a new character of the same class. Taking a look at the main builds in Diablo 2 there were more then one viable option per class:
Sorceress had Fire sorcs, Orb/Blizzard sorcs or lightning sorcs and combinations/hybrids of them with varying results.
Paladins had a few builds as well, auradin, hammer pally's and zeal/fanat pally's etc.
Zons came it bowazon or javazons, etc.
D2 made us as players identify with a play style we liked and build the character in that direction. If we messed up on skills we had to reroll the character, and later I believe there was a way to use the cube to reroll stats once or something like that.
If we compare two characters in D2 of the same build and items, they still may not be the same due to different stat point distribution, there was still diversity. Yes there were optimal stats like min strength for gear and the rest into life for sorcs etc.. but at least there was an option to experiment; especially since certain skills allowed mana to be depleted instead of life, one could then put points into mana with good results.
The above example in D3 would render the characters identical save for gear, the difference not based on stat point decisions but on random luck of item rolls or AH purchases.
The point is though that having to reroll a character whether to try a different build or to improve your character, made you invest some thought into your character, in some cases plan ahead and even collect specific gear for your desired build.
This brings me to the second point, itemization.
Two points about D3 I'd like to mention at this time.
a) D3 is too end game focused without catering to end game.
b) D2 had items; rune words, sets and uniques that made the low and mid ranges fun to play.
You see in D3 no one cares for low level items, the goal is to get to level 60 and never look back again. However in D2 lets say you were doing Meph runs and got a sigon piece during a Hell Meph run with your level 96 Hammer Pally.
It might seem like a bad drop, but not if you had a low level character you were planning to build up. Then the drop becomes not SO bad, but more on the lines of "oh well I didn't get a shako, BUT hey I now have a full set of sigons for my level 6 Zeal Paladin to use while leveling up in normal."
D3 has no use for ANY low level Uniques or sets. Once you have one of each character at level 60 they are all useless, making 75% of the game content useless.
This is perhaps the saddest part of all: 75% of the game is never seen again.
I played D2 for many years, but I did not play the SAME character for all those years. I built up many characters from low level to high level in order to experiment with different buildsadd a bit more str or mana instead of some other stat to see if it was effective. D3 provides none of this.
D2's itemization was good. I'm not going to say it was amazing, however it was at least well thought out.
When thinking of what made an item godly in D2 to what makes an item godly in D3, there is a huge difference. Lets take it down a notch to comparing good items in D2 for example a shako.
What made one shako worth an Um rune or an Ist rune was all of about 6 defense points.
Perfect numbers were more for bragging rights and were worth more, while low end numbers on a good item still made the item worth using! A few defense points didn't make the item useless.
D3 has legendary items where there are hundreds of factors that determine if it is good or completely unusable. So much so, that apart from its visual appearance and name, it's a completely different item.
While legendaries should have some varying stats, they should still be the same item! A legendary Wand with it's main reason to exist for a wizard should never have str or dex inplace of int. These items can have a str bonus, but it should be small, example.
300 int, 50str, 50 dex, 100 vit
Could be made randomized to allow 250-350 int, 40-60 str, 40-60 dex, 50-150 vit (with the int stat always on it).
However, never 200 str, 100 dex, 50 int or no int at all. This makes no sense, and certainly such a legendary item geared for a wizard would never exist as a legendary item in a world where magical items could exist. If they did, they certainly would not be considered "legendary."
I believe the devs are working on this problem, but it needs to be stated again.
3. Things To Do, replayability and Goals
So if you read section 1 and 2, you might be wondering;
Why make new characters and collect low level loot anyway?
Again using D2 as a reference; There was a purpose to make new characters, not only to try new build styles or optimize stats but for items in the game.
For those who played D2, there was a wonderful quest in act 4 where you got to smash a soul stone which gave you a chance at some runes. In hell mode you had a chance to get a rune up to GUL. The catch was that you could only do the quest once per mode per character. In my opinion a great way to add replay ability into the game.
So what to do? Well re-roll a new character, rush through normal, nightmare and hell to do the soul stone quests and yet another chance at some good runes... think pul,um,mal,ist,gul.
You could then use the CUBE to combine runes and upgrade them to the next tier up!
What this did was make collecting low level sets and unique items useful and reusable!
Why? for things like TRIST Runs, rolling through to the next difficulty and then passing them on to your new low level character. This was FUN! and it gave normal and nightmare modes more replay time then they ever get now in D3. The way it is now, everyone gets to inferno and never looks back. 4 difficulties and 3 of them never see the light of day again... once again 75% of the game made obsolete.
D2 at least made some use of visiting each act again with its quest mechanics.
D3 in itself is not a bad game, but there could be some tweaks that make it a great game. Some tweaks I realize would be very hard to code, perhaps unlocking the ability to manage your stat points is a programming nightmare this late in the game so to speak. However there are things that could be done that should not be so hard to do.
1. Make normal, nightmare and hell modes worth revisiting by adding once per character per mode quests, similar to the soul stone in D2. Make the quest worthwhile so as to compel me to make a new character in order to repeat it. We have 10 character slots and only 5 characters, I wouldn't mind making a character or two just for this purpose.
Example quest based on gems currently in game:
• normal mode gem quest: random drops 3-5 gems with 1-2 having a chance at max quality flawless square.
• nightmare mode gem quest: random drop 3-5 gems with 1-2 having a chance at max quality radiant square.
• Hell mode gem quest: random drop 3-5 gems with 1-2 having a chance at max quality flawless star.
• Inferno mode gem quest: random drop 3-5 gems with 1-2 having a chance at max quality Radiant Star.
Preferably to existing gems change the above with a chance to drop a gem type not found or crafted elsewhere in the game.
2. Make certain items only possible to drop at certain character levels. Or even better make a craft-able item where certain parts only drop at certain character levels in specific difficulties on a specific champ set or purple champ.
Example: Abyssal Locket (4 pieces)
• Sapphire shard, normal mode character level 10-20
• Ruby shard, nightmare mode character level 30-40
• diamond shard, hell mode character level 45-60
• Demonic Silver, inferno mode character level 60
Combine these to create an Abyssal Locket (or Mara's real kaleidoscope)
These two examples alone would add to the game by creating replay ability and not have characters become overpowered.