See that large number on the time played above? Yeah that has only been since it got on Steam.
Yes the graphics are dated and some of the base D&D mechanics are creaking under the weight of all the add-ons done over the years. Most of the problems with mechanics tend to show up at the upper level ranges (20+)
Many of the recent adjustments to classes has taken some of the difficulty edge off of the lower levels as power creep has reared its head.
For the absolute best DDO experience:
get 3-4-5 friends that have zero experience playing. Have everyone go through the tutorial (it is solo only).
Set up a schedule of play time and request that no one plays at all outside of the group time, no spoilers!
Dont go read about how best to play the game or the best builds , etc.
The exploration and learning on your own when it is all fresh to the whole crew is priceless.
Some dungeons have you thinking with your fighter ,barbarian or sorcerer you are the baddest MoFo ever.
Next dungeon you are cheering on the rogue who is sneaking around a room full of big, bad Ogres, that would squash him in no time flat if they see him/her, picking up the soul stones(dead PCs) of the entire party to take them back to the shrine to be raised from the dead.
Lots to do as free to play so no need to pull out the CC right away.
If you follow the above plan for best experience by time you get to where you feel the 'need' to pay, you will gladly be screaming "take my money, now!"
One word of caution about making characters;
Many of the older dungeons have the unfortunate MMO min/maxer design problem.
You will run in to somethings that require X Strength score to open or Y skill points to trick an NPC will seem really high.
The desiginers couldn't make the stat requirements too low where a balanced character could complete with out making things trivial for the min/maxers.
Just keep that in mind when building that maxing or nearly maxing your primary ability scores is suggested and likewise it is better to have a few skills that are maxed rather than a bunch of skills with low investment.
Still haven't experienced anything quite like it after years and years I still keep playing.
Noobstyle with friends is the best but super deep to keep even power gamers happy for a long, long time.