How many systems does a game like D&D need?

I've written before about unique class systems in D&D, but how many should there be? Clearly older editions, like Second Edition, had a bloat of independent systems. Third edition did wonders to try to unify many of these with the d20 mechanic (pick up a d20, roll high). Fourth edition rolled back some of these systems, or at least rolled them higher into the game's math. The early classes from the first two players' handbooks (and some from the third) followed the same template of at-will, encounter, and daily powers. But each class had its own unique (and often lengthy) list. Also, systems like feats and action points had every class participate, though feats might be restricted.

I think spells are one great system where powers can be shared. Even if there is a distinction between Arcane and Divine (And Primal? And Psionic?) magic, allowing classes like the sorcerer, warlock, and wizard to share spells means that no one class will get all the support (I'm looking at you, 4e Wizard/Mage/Witch/Sha`ir/Bladesinger especially compared to the artificer, swordmage, runepriest, and seeker). I think 4e discovered this in the essentials run, but it would have been great if there were more power-source based powers that all martial or arcane classes could share.

Forgotten Innovations: Character Points

AD&D character points were the last in the line of extravagant excess that TSR unleashed before Wizards of the Coast took control of the game.

In my forced exile from gaming, I've been known to read a few forums now and then. I used to enjoy reading some of the speculationa about D&D Next, but now they mostly seem pretty similar. And a lot of people are requesting innovations that showed up much earlier in the life of the game.

One of these forgotten innovations is character points from 2nd Edition. Now, second edition is often maligned as the dark ages of D&D. TSR went broke, and the game suffered from an excess of options. This is particularly true with the Player's Option line (including the Dungeon Master's Option: High Level Campaigns).

Man, wouldn't it be sweet if feats were broken down according to usefulness and quality so that each one could just be bought with a pool of points?

Anonymous forum poster that I'm paraphrasing, you've stumbled upon one of the so-called excessive options of 2nd Edition. Each class and race had options that could be purchased with character points. Want to be able to get weapon specialization as a Ranger? Want to access some wizard spells as a cleric? Want a signature spell as a wizard? All of this (and more) was available with character points.

Now, this was probably somewhat broken because they can be combined in an astounding array of bad ways. This sort of imbalance could be alleviated now with a large playtest of dedicated nerds, the type of thing the internet currently allows and Wizards of the Coast is trying for. The modern CharOp boards would have a field day finding all the brokenness that character points allowed. Heck, I found some awesome combinations back in the day.