The problem I have with 4e is that it is moving away from simulation to cinematic. I like simulation RPGs. I do not like cinematic RPGs.
To give an example, Firecube is a big problem for me. I know that a lot of people feel that the simplicity of being able to count one square as one square, even when going diagonal, is worth the anomaly, but for me it breaks my willing suspension of disbelief. I find myself going, “That’s stupid! How hard is it to make a circle on a grid map? Here, I can do it in two seconds!” The simulationist gamer in me just goes berserk.
Of course I can house rule the diagonal movement, but it is just one example of many.
I don’t like the use of cards. These are optional, but you can use "Power cards" to track your abilities and whether you have used them or not. It smacks of D&D: the Gathering.
I don’t like the new roles (Striker, defender, controller, leader): Dungeons of Warcraft.
I don’t like that angels are no longer Good: Now you have more monsters to kill! Seriously, angels are no longer Good so that they don't waste space in the Monster Manual on monsters that you will never fight.
I don’t like the new demons and devils: Devils have wings, demons don’t. (What are they? Autobots and Deceptigons?)
I don’t like Healing surges: The 30th level epic cleric can heal an army of wounded, but he can’t heal you (you used all your healing surges). You are done for today, take a six hour nap and you’ll be fine. You are fully healed and have all your powers back ofter 6 hours of rest.
I don’t like how recharge chances are listed as “Recharge: 4 5 6”. Like I can’t figure out that I need to roll a 4 or higher on a d6 if they just put “Recharge: 4” there? (It is a nitpick I know, but really it makes me think they are questioning my intelligence.)
Minions. All minions have 1hp. I find it hilarious that an ogre that might take 100 points of damage to drop when you are 3rd level, will die with a single dagger thrust from the wizard at 10th level. At 3rd level he was the “boss”, but at 10th he is just the Giant’s minion.
There is more, but you get the idea.
I guess I can sum up everything above with the simple statement that I fundamentally disagree with WotC’s design philosophy for 4th edition.