I've always loved dnd, been playing since Ad&d but never stayed in one place long enough to ever get a character past 7th level so I've never had the experience of a truly high level game.
Another difficulty i've had now that I'm older with a young child and my social group having changed to mums and dads of my son's friends at playcentre and kindergarten, is actually finding anyone with time or interest to learn and play dnd with me.
I've finally managed to generate the interest, now having established a 1 per month session with friends who have never played dnd before. Time is still a problem but with a lot of patience we get around the 'kids-chaos' factor.
I began the campaign in 3.5, and shortly after 4th ed was announced. We still ran the game and their characters managed to finish their first major quest and level up.
I held off levelling up til my new 4th ed books arrived and then convinced the players to reinvent their characters to fit the new system but beginning them at 2nd level, assuming that what they had achieved until then had still happened even though their characters were changed (for example a half orc barbarian was no longer possible). Everyone agreed and we've had 4 sessions of 4e and I'm pretty sure during the next session they will complete their next major quest and level to 3rd.
I give all this detail so you know which angle I'm coming from. Now I get to the point; the experience of the wizard has changed drammatically from 3.5 to 4th ed. I had tried to explain to him when he made his 3ed wizard that from level 1 to 5 was basically an exercise in survival. From 5th level he would be the one pulling the big punches... til then he was going to be the gimp. Which was how it was. He spent nearly every session firing off his one spell and then have nothing to do for the rest of that game day. He had a bow (elven wizard) and the one time he tried to use it (out of sheer bored frustration) he missed by just enough to nail the half-orc in the back. So he basically became the babysitter, appearing back at the table with little interest when it was his turn to say: I guess I defend myself in the corner again...
Since we've been playing 4e his entire attitude is changed. He's in the game, wiping crowds of minions with flaming hands, opening closed portcullis levers through the portcullis with mage hand, tossing lit coins out into the darkness and lighting his companions torches in an instant, teleporting to defensive high positions and nailing enemies from afar with a hail of magic missiles... thats not to mention having been able to take a feat for leather armour, defend himself with his staff, roast his enemies with a rolling sphere of fire, not die from one hit, and to have an ac comparable to the rest of his companions...
I realise that this is the point of view from someone who is new to the game, but in my opinion all points of views should be taken into account, and certainly a new player's point of view is just as valid as a veteran's. It's through new players that the game will continue to grow after all.
The rest of the group (also all new players with no other roleplaying experience) are all very happy with the changes in 4e. Individually they have each confirmed they prefer it to 3.5. I'm sure one of the reasons has been a change in my attitude as a DM from: 'no, you can't do that, you're just a first level weakling... try at but at you're own risk, this is going to be very hard and if you fail you will suffer the consequences' to the 'say yes to your players and let them have fun' which is what I get from 4e. I feel a lot of freedom with the new system, and whatever its flaws or seeming limitations, well I can fill them in with my imagination and creativity, and keeping the 'say yes philosophy' I know that my players have appreciated the change. They percieve there characters as mighty heroes now, not 2nd level weaklings. I'm sure thats a philosophy I could and definitely would take if I run another 3e game in the future, nevertheless where I found that 'freedom to have fun' was with 4e.