1. Elimination of cross class skills.
2. More skill points.
3. More options from the core book in terms of what characters can and can't do with explanations being used in part role playing terms (background) and mechanical terms (what the abilities actually do.)
4. Elimination of % to stablizie.
5. Turning rules that follow rule #3. Turning shouldn't need feats to become specialized. It's a power source. Now what can be done with it from the core book?
6. Armor as DR. Despite the use of various types of armor class including touch, flat footed, and regular, it seems odd.
7. Hit Point negatives that change as your rise in level. No reason that a 20th level fighter should die at the same negative total that the 1st level fighter does.
8. Very simple list of core weapons with a few pages of 'equivilent' weapons so that GMs can quickly customize the weapon lists for their own game without needing pages and pages of game stats.
9. Moving of 'game breaking' spells to higher levels in the new 1-30 range (teleport, raise dead, etc...)
10. DMG must open the game system so that it supports multiple types of game play from high fantasy with low magic (Wheel of Time, Elric) to Sword and Sorcery style games (Conan, Fafrd, Historical) without needing complete redux for monster CR assumptions and magic item assumptions.
11. Elimination of random rolled hit points as default.
12. Elimination of random rolled game stats as default.
13. Higher survivability for low level characters. No pet, like a house cat, should be able to kill a 1st level mage.
14. Utility for low level characters. Low level characters should not get hit by a battle axe and have to rest for the day. They should not cast one spell and have to rest for the day.
15. Better explanations of starting character levels for various levels of gaming. The core rules have a very much "start at first level" feel. The DMG has to go into pages and pages of how to start characters at higher levels.
16. Make combat a skill.
17. Do something with saving throws. The game has many problems in the spell casting area where spells sometimes require a to hit roll, and a saving throw, and reduced effects, etc.... If you're hit by a fire ball, sucks to be you. Hope that armor protects you. You don't get to magically avoid the fire because you made a saving throw.
18. Core book builds on bogus fantasy by eliminating bard, druid, monk classes or makes those options you can build on the martial/skilled type characters.
19. Monsters that are simple to use and simple to understand. Monsters that professional designers can get right the first time to streamline the amount of screw ups that are fairly standard.
20. Reducation/elimination of different bonuses. Great idea in theory but never keept to a small enough pool to be very useful. "holy, luck, circumstance, etc..." blah. Either make them additive up to double the initiatl bonus or make it higher bonus with other bonuses coming in after durations expire.
21. Action Points that are meaningfull all the way to 30th level with abilities that increase as you raise in level with options to do more things with them but give players who 'hoard' them a reason to do so. (minor xp bonus, ability to turn them in when changing levels, etc...)
22. Elimination of the CR = XP. "Players should advance in levels every 13 challenging encounters or when the GM feels that they need to be a higher level to progress in the story." The time wasted adding xp, divinding by character levels, etc... is just that, wasted. True 20 did things right there.
23. Elimination of stats that follow a fomula for all stats and all classes or elimination of the stat and just the bonus. Why bother having a 3-18 scale when it could be a -4 to +4 scale? Less math = more fun. There is no reason going forward why WoTC shouldn't ape True 20 on this. "What's my bonus? I have a 17 strength. Is that +3 or +4. Well, -10, then divided by 2, then round down..." No. I have a +3 strength. What's my bonus? +3? Damn, that's simple!
24. Strength does not effect to hit rolls. To damage rolls, sure.
25. Favored Character Class: This becomes something that gives you a bonus when you stay it in, not encourages you to multiclass into other classes because you don't get an XP penalty. Stat bonuses in primary abilities, feat trees that require you be a certain level in the favored character class, etc...
26. Elimination of attacks of opportunity. Put them in an 'advanced' appendix alongside grappling, hit location tables, and other potentially useful, but game slowing mechanics.
27. Establish NPC classes that do not use the same rules as characters if the story doesn't call for it with rules on training for NPCs to explain their higher skill rolls, or provide numerous examples of how low level characters can be 'the best in the land' without being high level in terms of circumstance bonus, taking 20, skill focus feats, etc...
28. Redistribution of feats. No feats should obviously suck. Toughness, I'm looking at you. Dodge, I'm looking at you.
29. Talents/Birth Abilities: Only taken at first level gives the character a little 'oomph' in his field. Think Background options from Rolemaster.
30. More feat aquisition. One of the most annoying things about d20 is that that are thousands of feats but unless you're playing fifty characters at a time, you'll only get to use a handful of them.
31. More material on role playing and role playing styles in the Player's Handbook. Not in the Dungeon Maste'rs Guide. Not in some Dummies book. Not in the Player's Handbook II. In the core Player's Handbook. Provide numerous examples of such.
32. In terms of #10, alignments should go away and be retained as an option for 'classic' flavor. The game currently has far too many factors built into it to allow easily elimination of it. A new edition could provide alignment as option rules. So many game systems don't have alignment, and while it has it's charms, it's a lazy GM's tool to keep the players in line as opposed to the dreaded tools of psychological disadvantages or just trusting the players to trust each other.
33. Board Game Support: Basic D&D had several adventures that had great maps to go with them. I want some board games that come with adventure maps, all the necessary miniatures and customized GM screens for that adventure. I want it to serve double duty for my other fantasy games, and I want to be able to use them for my D&D miniature games.
34. Don't screw up the electronic support. Yeah, lots of big talk now but hell, I had a 3.0 PHB. I had the little demo disk that came with it. WoTC screwed the pooch on that one. Lots of promise, lots of potential with no good resolution and a lot of 3rd party support of various quality.
35. Electronic/PDF releases of books should cost 50% of the hardcopy of the book. They should also be updated frequently with errata, FAQ, and rules revisions, not relying on the original purchaser to make due or buy a compendium for the changed versions.
36. Restructure the way size works in the game. A horse is not a 10 by 10 creature. The miniatures for trolls, ogres, hill giants, fire giants, frost giants, etc... should not almost be identical in size. Dragons should not have to be made to look like they're taking a dump because if they were sized to fit on their base they'd look too small. Come up with new ways to work these tools.
37. Cross-reference your own books. GMs should not see five different feats that ALMOST do the exact same thing. WoTC has no problem repritning swift and immediate actions, don't worry if you reprint the luck feat instead of having the luck feat, the luck of the gods feat, the rogue's luck feat, etc... where each one does somethign different.
38. Cross-reference your own books Part II: Be aware of what's come out an be helpful editors and writers and put side bars into the books to note what 'mash ups' can result from what books and what should be disallowed based on flavor text, mechanical results, etc... Don't act like players are not potentially min-maxers and that GMs are wise sages there to handle WoTC inability to keep their own game straight.
39. Spell Resistance: Similair to saving throws. It's too huge a blanket and effects too much of the game. Provide ways for monsters to get around the 'big' effects that can get rid of them quickly without nerfing them. Fire giants for example, immune to fire. Works in it's own way. Something like DR for spells as opposed to an all or nothing and then the inevitable saving throws?
40. With the understanding that an abiliity is an ability is an ability, elimination of the whole ECL vs level vs CR vs racial hit dice. Some type of restructuring where playing a powerful monster doesn't cripple your options. Got the ability to use your power multiple times a day? Great. So does the monk, fighter, rogue, and other classes. They are not considered an ECL + hit dice effort.